Insulative support for very high speed electrical interconnection

ABSTRACT

An electrical connector module with openings in an insulative support selectively positioned to limit dielectric loss in a signal. The connector may include a first and second conductor including first and second sides between first and second edges. An insulative support holds the first conductor adjacent the second conductor and may have at least five pedestal portions, wherein the first pedestal portion contacts the first side of the first conductor, the second pedestal portion contacts the second side of the first conductor, the third pedestal portion contacts the first side of the second conductor, the fourth pedestal portion contacts the second side of the second conductor, and at least a portion of the fifth pedestal portion is disposed between two edges of the first and second conductors. The pedestal portions may have widths less than the widths of the first and second sides of the first and second conductors.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/806,402, filed on Mar. 2, 2020, entitled “INSULATIVE SUPPORT FOR VERYHIGH SPEED ELECTRICAL INTERCONNECTION,” which is a continuation of U.S.application Ser. No. 16/358,143, filed on Mar. 19, 2019, entitled“INSULATIVE SUPPORT FOR VERY HIGH SPEED ELECTRICAL INTERCONNECTION,”which claims priority to and the benefit of U.S. Provisional PatentApplication Ser. No. 62/776,349, filed on Dec. 6, 2018, entitled“INSULATIVE SUPPORT FOR VERY HIGH SPEED ELECTRICAL INTERCONNECTION.”U.S. application Ser. No. 16/358,143 also claims priority to and thebenefit of U.S. Provisional Patent Application Ser. No. 62/647,517,filed on Mar. 23, 2018, entitled “INSULATIVE SUPPORT FOR VERY HIGH SPEEDELECTRICAL INTERCONNECTION.” The entire contents of these applicationsare hereby incorporated herein by reference in their entirety.

BACKGROUND

This patent application relates generally to interconnection systems,such as those including electrical connectors, used to interconnectelectronic assemblies.

Electrical connectors are used in many electronic systems. It isgenerally easier and more cost effective to manufacture a system asseparate electronic assemblies, such as printed circuit boards (“PCBs”),which may be joined together with electrical connectors. A knownarrangement for joining several printed circuit boards is to have oneprinted circuit board serve as a backplane. Other printed circuitboards, called “daughterboards” or “daughtercards,” may be connectedthrough the backplane.

A known backplane is a printed circuit board onto which many connectorsmay be mounted. Conducting traces in the backplane may be electricallyconnected to signal conductors in the connectors so that signals may berouted between the connectors. Daughtercards may also have connectorsmounted thereon. The connectors mounted on a daughtercard may be pluggedinto the connectors mounted on the backplane. In this way, signals maybe routed among the daughtercards through the backplane. Thedaughtercards may plug into the backplane at a right angle. Theconnectors used for these applications may therefore include a rightangle bend and are often called “right angle connectors.”

Connectors may also be used in other configurations for interconnectingprinted circuit boards and for interconnecting other types of devices,such as cables, to printed circuit boards. Sometimes, one or moresmaller printed circuit boards may be connected to another largerprinted circuit board. In such a configuration, the larger printedcircuit board may be called a “mother board” and the printed circuitboards connected to it may be called daughterboards. Also, boards of thesame size or similar sizes may sometimes be aligned in parallel.Connectors used in these applications are often called “stackingconnectors” or “mezzanine connectors.”

Regardless of the exact application, electrical connector designs havebeen adapted to mirror trends in the electronics industry. Electronicsystems generally have gotten smaller, faster, and functionally morecomplex. Because of these changes, the number of circuits in a givenarea of an electronic system, along with the frequencies at which thecircuits operate, have increased significantly in recent years. Currentsystems pass more data between printed circuit boards and requireelectrical connectors that are electrically capable of handling moredata at higher speeds than connectors of even a few years ago.

In a high density, high speed connector, electrical conductors may be soclose to each other that there may be electrical interference betweenadjacent signal conductors. To reduce interference, and to otherwiseprovide desirable electrical properties, shield members are often placedbetween or around adjacent signal conductors. The shields may preventsignals carried on one conductor from creating “crosstalk” on anotherconductor. The shield may also impact the impedance of each conductor,which may further contribute to desirable electrical properties.

Examples of shielding can be found in U.S. Pat. Nos. 4,632,476 and4,806,107, which show connector designs in which shields are usedbetween columns of signal contacts. These patents describe connectors inwhich the shields run parallel to the signal contacts through both thedaughterboard connector and the backplane connector. Cantilevered beamsare used to make electrical contact between the shield and the backplaneconnectors. U.S. Pat. Nos. 5,433,617, 5,429,521, 5,429,520, and5,433,618 show a similar arrangement, although the electrical connectionbetween the backplane and shield is made with a spring type contact.Shields with torsional beam contacts are used in the connectorsdescribed in U.S. Pat. No. 6,299,438. Further shields are shown in U.S.Pre-grant Publication 2013-0109232.

Other connectors have shield plates within only the daughterboardconnector. Examples of such connector designs can be found in U.S. Pat.Nos. 4,846,727, 4,975,084, 5,496,183, and 5,066,236. Another connectorwith shields only within the daughterboard connector is shown in U.S.Pat. Nos. 5,484,310, 7,985,097 is a further example of a shieldedconnector.

Other techniques may be used to control the performance of a connector.For instance, transmitting signals differentially may also reducecrosstalk. Differential signals are carried on a pair of conductingpaths, called a “differential pair.” The voltage difference between theconductive paths represents the signal. In general, a differential pairis designed with preferential coupling between the conducting paths ofthe pair. For example, the two conducting paths of a differential pairmay be arranged to run closer to each other than to adjacent signalpaths in the connector. No shielding is desired between the conductingpaths of the pair, but shielding may be used between differential pairs.Electrical connectors can be designed for differential signals as wellas for single-ended signals. Examples of differential electricalconnectors are shown in U.S. Pat. Nos. 6,293,827, 6,503,103, 6,776,659,7,163,421, and 7,794,278.

SUMMARY

Aspects of the present disclosure are related to an electrical connectorconfigured to reduce dielectric loss.

According to one aspect of the present application, an electricalconnector module is provided. The electrical connector module includes:at least two conductors, each of the at least two conductors including:a first end and a second end, and an intermediate portion connecting thefirst end and the second end, the intermediate portion comprising afirst edge and a second edge and a first side and a second side betweenthe first edge and the second edge, the first and second sides beingwider than the first and second edges, wherein the at least twoconductors comprise a first conductor and a second conductor; and aninsulative support holding the first conductor adjacent the secondconductor, the insulative support having a first pedestal portion, asecond pedestal portion, a third pedestal portion and a fourth pedestalportion, wherein the first pedestal portion contacts the first side ofthe first conductor, the second pedestal portion contacts the secondside of the first conductor, the third pedestal portion contacts thefirst side of the second conductor, and the fourth pedestal portioncontacts the second side of the second conductor, and, wherein the firstpedestal portion and the fourth pedestal portions have widths less thanthe widths of the first and second sides of the first and secondconductors.

According to one aspect of the present application, an electricalconnector is provided. The electrical connector includes: a plurality ofsignal conductors, wherein the signal conductors are configured toproduce an electric field pattern when carrying a low voltagedifferential signal at a frequency of 40 GHz, the field pattern definingregions of higher and lower electric field strength; and insulativematerial holding the plurality of signal conductors, wherein theinsulative material includes a plurality of openings along at least aportion of a length of signal conductors of the plurality of signalconductors, wherein the openings are selectively positioned with respectto regions of the higher electric field strength such that dielectricloss exhibited by a 14 GHz 50 millivolt differential signal is at least10% less in comparison to an insulative housing without openings.

According to one aspect of the present application, a method ofmanufacturing a module for an electrical connector is provided. Themethod includes: positioning a central member of an insulative supportbetween at least two conductors, each of the at least two conductorscomprising: a first end and a second end; and an intermediate portionconnecting the first end and the second end, the intermediate portioncomprising a first edge and a second edge and a first side and a secondside between the first edge and the second edge, the first and secondsides being wider than the first and second edges, wherein the at leasttwo conductors comprise a first conductor and a second conductor, andthe central member comprising a first pedestal portion and a secondpedestal portion, wherein the first pedestal portion contacts the firstside of the first conductor and the second pedestal portion contacts thefirst side of the second conductor; positioning a first cover and asecond cover of the insulative support adjacent to the first conductorand the second conductor respectively, each of the first and secondcover comprising a respective pedestal portion, wherein the pedestalportion of the first cover contacts the second side of the firstconductor and the pedestal portion of the second cover contacts thesecond side of the second conductor, and wherein a portion of at leastone surface of each conductor is exposed within an opening between thecentral member and a cover of the first and the second cover; andsurrounding at least a portion of the covers and the central member withone or more reference conductors.

The foregoing is a non-limiting summary of the invention, which isdefined by the attached claims.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In thedrawings, each identical or nearly identical component that isillustrated in various figures is represented by a like numeral. Forpurposes of clarity, not every component may be labeled in everydrawing. In the drawings:

FIG. 1 is an isometric view of an illustrative electricalinterconnection system, in accordance with some embodiments;

FIG. 2 is an isometric view, partially cutaway, of the backplaneconnector of FIG. 1;

FIG. 3 is an isometric view of a pin assembly of the backplane connectorof FIG. 2;

FIG. 4 is an exploded view of the pin assembly of FIG. 3;

FIG. 5 is an isometric view of signal conductors of the pin assembly ofFIG. 3;

FIG. 6 is an isometric view, partially exploded, of the daughtercardconnector of FIG. 1;

FIG. 7 is an isometric view of a wafer assembly of the daughtercardconnector of FIG. 6;

FIG. 8 is an isometric view of wafer modules of the wafer assembly ofFIG. 7;

FIG. 9 is an isometric view of a portion of the housing of the waferassembly of FIG. 7;

FIG. 10 is an isometric view, partially exploded, of a wafer module ofthe wafer assembly of FIG. 7;

FIG. 11 is an isometric view, partially exploded, of a portion of awafer module of the wafer assembly of FIG. 7;

FIG. 12 is an isometric view, partially exploded, of a portion of awafer module of the wafer assembly of FIG. 7;

FIG. 13 is an isometric view of a pair of conducting elements of a wafermodule of the wafer assembly of FIG. 7;

FIG. 14A is a side view of the pair of conducting elements of FIG. 13;

FIG. 14B is an end view of the pair of conducting elements of FIG. 13taken along the line B-B of FIG. 14 A;

FIG. 15 is a cross-sectional view of a pair of conducting elements withequipotential lines;

FIG. 16A is a cross-sectional view of an alternative embodiment of awafer module of FIG. 8, along the line 16-16, configured to reducedielectric loss, according to an illustrative embodiment;

FIG. 16B is a cross-sectional view of a wafer module of FIG. 16A, at adifferent location than shown in FIG. 16A;

FIG. 16C is a cross-sectional view of a wafer module of FIG. 16A, at adifferent location than shown in FIGS. 16A and 16B;

FIG. 17 is a cross-sectional view of a wafer module configured to reducedielectric loss, according to an illustrative embodiment; and

FIG. 18 is a cross-sectional view of a wafer module configured to reducedielectric loss, according to a further illustrative embodiment.

FIG. 19 is an isometric view of a wafer, partially cutaway to reveal aportion of a wafer module with edge-coupled signal conductors configuredto reduce dielectric loss, according to an illustrative embodiment.

FIG. 20A is a cross sectional view of a wafer module with edge-coupledsignal conductors configured to reduce dielectric loss, according to afurther illustrative embodiment.

FIG. 20B is a cross sectional view of the wafer module of FIG. 20A,cross-sectioned at a different location.

FIG. 21A is a partially exploded view of a connector module withedge-coupled signal conductors, according to an illustrative embodiment.

FIG. 21B is a partially exploded view of a connector module, accordingto an illustrative embodiment.

FIG. 22 is a partially exploded view of a wafer, according to anillustrative embodiment.

FIG. 23 is a partially exploded view of a vertical connector, accordingto an illustrative embodiment.

DETAILED DESCRIPTION

The inventors have recognized and appreciated techniques for increasingthe performance of a high density interconnection system, particularlythose that carry very high frequency signals that are necessary tosupport high data rates, by selectively positioning dielectric materialadjacent signal conductors so as to limit dielectric loss. Due to thegeometry of signal conductors, high frequency signals being carried onsignal conductors may create an electric field with spatially variableintensity. Where the electric field interacts with dielectric materialsupporting the signal conductors, there may be substantial dielectricloss experienced by a high frequency, e.g. 14, 24 or 40 GHz, signal.This dielectric loss may be mitigated by removing dielectric material atselect locations near the signal conductors. In accordance with someembodiments, dielectric material may be omitted adjacent edges of thesignal conductors. The inventors have recognized and appreciated that,in some embodiments, these regions contain higher electric fieldintensity.

The inventors have further recognized and appreciated techniques forstably retaining the signal conductors despite regions of omitteddielectric material. In accordance with some embodiments, the signalconductors may be suspended in one or more openings in the dielectricmaterial. The openings may be defined by and/or abut one or morepedestals in the dielectric material that is coupled to the signalconductor. The dielectric material may comprise a plurality of members,forming an insulative support for the signal conductors of a pair.

In some embodiments, one or more other members may encircle theplurality of insulative members, pushing them together such that thesignal conductors are pinched between the pedestal portions. In someembodiments, the members encircling the insulative support may be metaland, in some embodiments, may be grounded and may act as a shield forthe pair of signal conductors. Multiple encircling members maycollectively encircle each insulative support and those multipleencircle members may be held together with latches or insulativestructures. In some embodiments, corners of the insulative members maybe relieved so as to reduce variation in the pressure imposed on theinsulative members by the encircling members.

Open areas on the insulative support adjacent the edges of broadsidecoupled signal conductors are believed to reduce the insertion loss ofthe connector by, in some embodiments, 10-15% at frequencies such as 14GHz relative to a connector without open areas when the connectorcarries a low voltage differential signal, such as a 25 mV, 50 mV, 100mV, 250 mV, or 500 mV low voltage differential signal. The difference inattenuation may be 15-20% at 24 GHz, and even greater at higherfrequencies.

In some embodiments, an electrical connector module may be manufacturedto include at least two conductors and an insulative support holding theconductors between pedestal portions. Each of the first to conductorsmay include first and second ends connected by an intermediate portion,with the intermediate portion having two sides and two edges that arenarrower than the sides. The insulative support may have at least fourpedestal portions, with pair of pedestal portions contacting respectivesides of each of the at least two conductors. At least two of thepedestal portions may have widths less than the widths of the sides ofthe conductors.

In some embodiments, the insulative support comprises openings, andedges of the conductors are disposed within the openings. In someembodiments, the sides of the conductors have a first width, and theedges of the conductors each extend into the openings by a distanceequal to at least 10% of the first width. In some embodiments, the firstsurface and the second surface of the first conductor and the secondconductor are exposed within the openings.

In some embodiments, the conductors are held within the insulativesupport with the sides of the conductor being parallel. In someembodiments, the insulative support includes a first cover including afirst pedestal portion, a central member including a second pedestalportion and a third pedestal portion, and a second cover including afourth pedestal portion. In some embodiments, one or both cover(s)include a compliant portion between a first end and a second end, thefirst end and the second end of the cover(s) contact the central member,and a pedestal portion extends from the compliant portion.

In some embodiments, the electrical connector module includes at leastone shield around the insulative support, the at least one shieldpressing the compliant portion of a cover towards the central membersuch that a first conductor is pinched between the first pedestalportion and the second pedestal portion. In some embodiments, the atleast one shield comprises at least one metal member. In someembodiments, the at least one metal member comprises two joined metalmembers that collectively encircle the insulative support. In someembodiments, two shield members collectively encircle the insulativesupport. In some embodiments, the conductors are a broadside coupledpair of signal conductors and the shield is disposed around thebroadside coupled pair. In some embodiments, first ends of the signalconductors comprise mating contact portions, second ends of the firstand second signal conductors comprise contact tails, and the matingcontact portions and the contact tails extend from the insulativesupport. In some embodiments, the at least one of the covers comprises afirst side and an opposing side, the first pedestal portion extends froma central portion of the first side, portions of the opposing sidecontact the shield, and a central portion of the opposing side comprisesa groove, creating a space between the central portion and the shield.

In some embodiments, corners of the first end and the second end of theat least one cover are relieved so as the leave a space between thecorners and the at least one shield. In some embodiments, a subassemblyincludes at least two conductors, an insulative support, a first shieldmember, and a second shield member, and the electrical connector moduleincludes a wafer. The wafer may include multiple lossy members coupledto the first shield member and/or the second shield member of at leastone of a plurality of subassemblies disposed within the wafer. In someembodiments, a plurality of wafers are aligned in parallel to form anelectrical connector.

In some embodiments an electrical connector is provided. The electricalconnector includes a plurality of signal conductors, wherein the signalconductors are configured to produce an electric field pattern whencarrying a low voltage differential signal at a frequency of 40 GHz, thefield pattern defining regions of higher and lower electric fieldstrength, and insulative material holding the plurality of signalconductors, wherein the insulative material comprises a plurality ofopenings along at least a portion of a length of signal conductors ofthe plurality of signal conductors, wherein the openings are selectivelypositioned with respect to regions of the higher electric fieldstrength. In some embodiments, the dielectric loss exhibited by a 14 GHz50 millivolt differential signal is at least 10% less in comparison toan insulative housing without openings. In some embodiments, the lossexhibited by the 14 GHz differential signal is at least 15% less incomparison to an insulative housing without openings. In someembodiments, the loss exhibited by the 14 GHz low voltage differentialsignal is at least 0.5 dB less in comparison to an insulative housingwithout openings.

In some embodiments, at least one surface of each of the signalconductors of the plurality of signal conductors is exposed within theplurality of openings. In some embodiments, the signal conductors aresupported by pedestal portions of the insulative housing, with one ormore pedestal portions having respective widths that are narrower thanthe widths of the respective surfaces of the signal conductors.

In some embodiments, the signals conductors are arranged in a pluralityof rows, with first ends positioned to form a first interface and secondends positioned to form a second interface, and the first interface isat an angle with respect to the second interface such that each row ofthe plurality of rows is a different length. The dimensions of theopenings within a set of the signal conductors of a row may bedetermined based on the lengths of the set of the signal conductors ofthe row.

In some embodiments, a method for manufacturing a module for anelectrical connector is provided. The method may include positioning acentral member of an insulative support between at least two conductors.Each of the at least two conductors including: an intermediate portionconnecting a first end and a second end, the intermediate portioncomprising two edges and two sides between the edges, the sides beingwider than the edges. The central member may include a first pedestalportion and a second pedestal portion that contact respective portionsof a first and second conductor. The method may include positioning afirst cover and a second cover of the insulative support adjacent to thefirst conductor and the second conductor respectively, each of the firstand second cover comprising a respective pedestal portion that contactrespective sides of the conductors not in contact with the centralmember, wherein a portion of at least one surface of each conductor isexposed within an opening between the central member and one of thecovers. The method may further include surrounding at least a portion ofthe covers and the central member with one or more reference conductors.In some embodiments, the pedestal portions of the insulative supportdefine one or more openings in a dielectric material, and the method mayfurther include positioning one or more edges of the conductors in theone or more openings. In some embodiments, the method further includesforming wafers by, at least in part, positioning a plurality of lossymembers so that each lossy member is electrically coupled to a pluralityof reference conductors, and aligning the plurality of wafers. In someembodiments, the wafers are aligned in parallel.

Techniques for reducing dielectric loss as described herein may beapplied in connectors with broadside coupled pairs over all or a portionof their length. Such techniques may be applied in right angle or otherconnectors including broadside-coupled differential pairs. Suchtechniques may also be applied in vertical or other connectors withedge-coupled differential pairs.

FIG. 1 illustrates an electrical interconnection system of the form thatmay be used in an electronic system. In this example, the electricalinterconnection system includes a right angle connector and may be used,for example, in electrically connecting a daughtercard to a backplane.These figures illustrate two mating connectors. In this example,connector 200 is designed to be attached to a backplane and connector600 is designed to attach to a daughtercard. As can be seen in FIG. 1,daughtercard connector 600 includes contact tails 610 designed to attachto a daughtercard (not shown). Backplane connector 200 includes contacttails 210, designed to attach to a backplane (not shown). These contacttails form one end of conductive elements that pass through theinterconnection system. When the connectors are mounted to printedcircuit boards, these contact tails will make electrical connection toconductive structures within the printed circuit board that carrysignals or are connected to a reference potential. In the exampleillustrated the contact tails are press fit, “eye of the needle,”contacts that are designed to be pressed into vias in a printed circuitboard. However, other forms of contact tails may be used.

Each of the connectors also has a mating interface where that connectorcan mate—or be separated from—the other connector. Daughtercardconnector 600 includes a mating interface 620. Backplane connector 200includes a mating interface 220. Though not fully visible in the viewshown in FIG. 1, mating contact portions of the conductive elements areexposed at the mating interface.

Each of these conductive elements includes an intermediate portion thatconnects a contact tail to a mating contact portion. The intermediateportions may be held within a connector housing, at least a portion ofwhich may be dielectric so as to provide electrical isolation betweenconductive elements. Additionally, the connector housings may includeconductive or lossy portions, which in some embodiments may provideconductive or partially conductive paths between some of the conductiveelements. In some embodiments, the conductive portions may provideshielding. The lossy portions may also provide shielding in someinstances and/or may provide desirable electrical properties within theconnectors.

In various embodiments, dielectric members may be molded or over-moldedfrom a dielectric material such as plastic or nylon. Examples ofsuitable materials include, but are not limited to, liquid crystalpolymer (LCP), polyphenyline sulfide (PPS), high temperature nylon orpolyphenylenoxide (PPO) or polypropylene (PP). Other suitable materialsmay be employed, as aspects of the present disclosure are not limited inthis regard.

All of the above-described materials are suitable for use as bindermaterial in manufacturing connectors. In accordance some embodiments,one or more fillers may be included in some or all of the bindermaterial. As a non-limiting example, thermoplastic PPS filled to 30% byvolume with glass fiber may be used to form the entire connector housingor dielectric portions of the housings.

Alternatively or additionally, portions of the housings may be formed ofconductive materials, such as machined metal or pressed metal powder. Insome embodiments, portions of the housing may be formed of metal orother conductive material with dielectric members spacing signalconductors from the conductive portions. In the embodiment illustrated,for example, a housing of backplane connector 200 may have regionsformed of a conductive material with insulative members separating theintermediate portions of signal conductors from the conductive portionsof the housing.

The housing of daughtercard connector 600 may also be formed in anysuitable way. In the embodiment illustrated, daughtercard connector 600may be formed from multiple subassemblies, referred to herein as“wafers.” Each of the wafers (700, FIG. 7) may include a housingportion, which may similarly include dielectric, lossy and/or conductiveportions. One or more members may hold the wafers in a desired position.For example, support members 612 and 614 may hold top and rear portions,respectively, of multiple wafers in a side-by-side configuration.Support members 612 and 614 may be formed of any suitable material, suchas a sheet of metal stamped with tabs, openings or other features thatengage corresponding features on the individual wafers.

Other members that may form a portion of the connector housing mayprovide mechanical integrity for daughtercard connector 600 and/or holdthe wafers in a desired position. For example, a front housing portion640 (FIG. 6) may receive portions of the wafers forming the matinginterface. Any or all of these portions of the connector housing may bedielectric, lossy and/or conductive, to achieve desired electricalproperties for the interconnection system.

In some embodiments, each wafer may hold a column of conductive elementsforming signal conductors. These signal conductors may be shaped andspaced to form single ended signal conductors. However, in theembodiment illustrated in FIG. 1, the signal conductors are shaped andspaced in pairs to provide differential signal conductors. Each of thecolumns may include or be bounded by conductive elements serving asground conductors. It should be appreciated that ground conductors neednot be connected to earth ground, but are shaped to carry referencepotentials, which may include earth ground, DC voltages or othersuitable reference potentials. The “ground” or “reference” conductorsmay have a shape different than the signal conductors, which areconfigured to provide suitable signal transmission properties for highfrequency signals.

Conductive elements may be made of metal or any other material that isconductive and provides suitable mechanical properties for conductiveelements in an electrical connector. Phosphor-bronze, beryllium copperand other copper alloys are non-limiting examples of materials that maybe used. The conductive elements may be formed from such materials inany suitable way, including by stamping and/or forming.

The spacing between adjacent columns of conductors may be within a rangethat provides a desirable density and desirable signal integrity. As anon-limiting example, the conductors may be stamped from 0.4 mm thickcopper alloy, and the conductors within each column may be spaced apartby 2.25 mm and the columns of conductors may be spaced apart by 2.4 mm.However, a higher density may be achieved by placing the conductorscloser together. In other embodiments, for example, smaller dimensionsmay be used to provide higher density, such as a thickness between 0.2and 0.4 mm or spacing of 0.7 to 1.85 mm between columns or betweenconductors within a column. Moreover, each column may include four pairsof signal conductors, such that a density of 60 or more pairs per linearinch is achieved for the interconnection system illustrated in FIG. 1.However, it should be appreciated that more pairs per column, tighterspacing between pairs within the column and/or smaller distances betweencolumns may be used to achieve a higher density connector.

The wafers may be formed any suitable way. In some embodiments, thewafers may be formed by stamping columns of conductive elements from asheet of metal and over molding dielectric portions on the intermediateportions of the conductive elements. In other embodiments, wafers may beassembled from modules each of which includes a single, single-endedsignal conductor, a single pair of differential signal conductors or anysuitable number of single ended or differential pairs.

Assembling wafers from modules may aid in reducing “skew” in signalpairs at higher frequencies, such as between about 25 GHz and 40 GHz, orhigher. Skew, in this context, refers to the difference in electricalpropagation time between signals of a pair that operates as adifferential signal. Modular construction that reduces skew is designeddescribed, for example in application 61/930,411, which is incorporatedherein by reference.

In accordance with techniques described in that application, in someembodiments, connectors may be formed of modules, each carrying a signalpair. The modules may be individually shielded, such as by attachingshield members to the modules and/or inserting the modules into anorganizer or other structure that may provide electrical shieldingbetween pairs and/or ground structures around the conductive elementscarrying signals.

In some embodiments, signal conductor pairs within each module may bebroadside coupled over substantial portions of their lengths. Broadsidecoupling enables the signal conductors in a pair to have the samephysical length. To facilitate routing of signal traces within theconnector footprint of a printed circuit board to which a connector isattached and/or constructing of mating interfaces of the connectors, thesignal conductors may be aligned with edge to edge coupling in one orboth of these regions. As a result, the signal conductors may includetransition regions in which coupling changes from edge-to-edge tobroadside or vice versa. As described below, these transition regionsmay be designed to prevent mode conversion or suppress undesiredpropagation modes that can interfere with signal integrity of theinterconnection system.

The modules may be assembled into wafers or other connector structures.In some embodiments, a different module may be formed for each rowposition at which a pair is to be assembled into a right angleconnector. These modules may be made to be used together to build up aconnector with as many rows as desired. For example, a module of oneshape may be formed for a pair to be positioned at the shortest rows ofthe connector, sometimes called the a-b rows. A separate module may beformed for conductive elements in the next longest rows, sometimescalled the c-d rows. The inner portion of the module with the c-d rowsmay be designed to conform to the outer portion of the module with thea-b rows.

This pattern may be repeated for any number of pairs. Each module may beshaped to be used with modules that carry pairs for shorter and/orlonger rows. To make a connector of any suitable size, a connectormanufacturer may assemble into a wafer a number of modules to provide adesired number of pairs in the wafer. In this way, a connectormanufacturer may introduce a connector family for a widely usedconnector size—such as 2 pairs. As customer requirements change, theconnector manufacturer may procure tools for each additional pair, or,for modules that contain multiple pairs, group of pairs to produceconnectors of larger sizes. The tooling used to produce modules forsmaller connectors can be used to produce modules for the shorter rowseven of the larger connectors. Such a modular connector is illustratedin FIG. 8.

Further details of the construction of the interconnection system ofFIG. 1 are provided in FIG. 2, which shows backplane connector 200partially cutaway. In the embodiment illustrated in FIG. 2, a forwardwall of housing 222 is cut away to reveal the interior portions ofmating interface 220.

In the embodiment illustrated, backplane connector 200 also has amodular construction. Multiple pin modules 300 are organized to form anarray of conductive elements. Each of the pin modules 300 may bedesigned to mate with a module of daughtercard connector 600.

In the embodiment illustrated, four rows and eight columns of pinmodules 300 are shown. With each pin module having two signalconductors, the four rows 230A, 230B, 230C and 230D of pin modulescreate columns with four pairs or eight signal conductors, in total. Itshould be appreciated, however, that the number of signal conductors perrow or column is not a limitation of the invention. A greater or lessernumber of rows of pin modules may be included within housing 222.Likewise, a greater or lesser number of columns may be included withinhousing 222. Alternatively or additionally, housing 222 may be regardedas a module of a backplane connector, and multiple such modules may bealigned side to side to extend the length of a backplane connector.

In the embodiment illustrated in FIG. 2, each of the pin modules 300contains conductive elements serving as signal conductors. Those signalconductors are held within insulative members, which may serve as aportion of the housing of backplane connector 200. The insulativeportions of the pin modules 300 may be positioned to separate the signalconductors from other portions of housing 222. In this configuration,other portions of housing 222 may be conductive or partially conductive,such as may result from the use of lossy materials.

In some embodiments, housing 222 may contain both conductive and lossyportions. For example, a shroud including walls 226 and a floor 228 maybe pressed from a powdered metal or formed from conductive material inany other suitable way. Pin modules 300 may be inserted into openingswithin floor 228.

Lossy or conductive members may be positioned adjacent rows 230A, 230B,230C and 230D of pin modules 300. In the embodiment of FIG. 2,separators 224A, 224B and 224C are shown between adjacent rows of pinmodules. Separators 224A, 224B and 224C may be conductive or lossy, andmay be formed as part of the same operation or from the same member thatforms walls 226 and floor 228. Alternatively, separators 224A, 224B and224C may be inserted separately into housing 222 after walls 226 andfloor 228 are formed. In embodiments in which separators 224A, 224B and224C formed separately from walls 226 and floor 228 and subsequentlyinserted into housing 222, separators 224A, 224B and 224C may be formedof a different material than walls 226 and/or floor 228. For example, insome embodiments, walls 226 and floor 228 may be conductive whileseparators 224A, 224B and 224C may be lossy or partially lossy andpartially conductive.

In some embodiments, other lossy or conductive members may extend intomating interface 220, perpendicular to floor 228. Members 240 are shownadjacent to end-most rows 230A and 230D. In contrast to separators 224A,224B and 224C, which extend across the mating interface 220, separatormembers 240, approximately the same width as one column, are positionedin rows adjacent row 230A and row 230D. Daughtercard connector 600 mayinclude, in its mating interface 620, slots to receive, separators 224A,224B and 224C. Daughtercard connector 600 may include openings thatsimilarly receive members 240. Members 240 may have a similar electricaleffect to separators 224A, 224B and 224C, in that both may suppressresonances, crosstalk or other undesired electrical effects. Members240, because they fit into smaller openings within daughtercardconnector 600 than separators 224A, 224B and 224C, may enable greatermechanical integrity of housing portions of daughtercard connector 600at the sides where members 240 are received.

FIG. 3 illustrates a pin module 300 in greater detail. In thisembodiment, each pin module includes a pair of conductive elementsacting as signal conductors 314A and 314B. Each of the signal conductorshas a mating interface portion shaped as a pin. Opposing ends of thesignal conductors have contact tails 316A and 316B. In this embodiment,the contact tails are shaped as press fit compliant sections.Intermediate portions of the signal conductors, connecting the contacttails to the mating contact portions, pass through pin module 300.

Conductive elements serving as reference conductors 320A and 320B areattached at opposing exterior surfaces of pin module 300. Each of thereference conductors has contact tails 328, shaped for making electricalconnections to vias within a printed circuit board. The referenceconductors also have mating contact portions. In the embodimentillustrated, two types of mating contact portions are illustrated.Compliant member 322 may serve as a mating contact portion, pressingagainst a reference conductor in daughtercard connector 600. In someembodiments, surfaces 324 and 326 alternatively or additionally mayserve as mating contact portions, where reference conductors from themating conductor may press against reference conductors 320A or 320B.However, in the embodiment illustrated, the reference conductors may beshaped such that electrical contact is made only at compliant member322.

FIG. 4 shows an exploded view of pin module 300. Intermediate portionsof the signal conductors 314A and 314B are held within an insulativemember 410, which may form a portion of the housing of backplaneconnector 200. Insulative member 410 may be insert molded around signalconductors 314A and 314B. A surface 412 against which referenceconductor 320B presses is visible in the exploded view of FIG. 4.Likewise, the surface 428 of reference conductor 320A, which pressesagainst a surface of member 410 not visible in FIG. 4, can also be seenin this view.

As can be seen, the surface 428 is substantially unbroken. Attachmentfeatures, such as tab 432 may be formed in the surface 428. Such a tabmay engage an opening (not visible in the view shown in FIG. 4) ininsulative member 410 to hold reference conductor 320A to insulativemember 410. A similar tab (not numbered) may be formed in referenceconductor 320B. As shown, these tabs, which serve as attachmentmechanisms, are centered between signal conductors 314A and 314B whereradiation from or affecting the pair is relatively low. Additionally,tabs, such as 436, may be formed in reference conductors 320A and 320B.Tabs 436 may engage insulative member 410 to hold pin module 300 in anopening in floor 228.

In the embodiment illustrated, compliant member 322 is not cut from theplanar portion of the reference conductor 320B that presses against thesurface 412 of the insulative member 410. Rather, compliant member 322is formed from a different portion of a sheet of metal and folded overto be parallel with the planar portion of the reference conductor 320B.In this way, no opening is left in the planar portion of the referenceconductor 320B from forming compliant member 322. Moreover, as shown,compliant member 322 has two compliant portions 424A and 424B, which arejoined together at their distal ends but separated by an opening 426.This configuration may provide mating contact portions with a suitablemating force in desired locations without leaving an opening in theshielding around pin module 300. However, a similar effect may beachieved in some embodiments by attaching separate compliant members toreference conductors 320A and 320B.

The reference conductors 320A and 320B may be held to pin module 300 inany suitable way. As noted above, tabs 432 may engage an opening 434 inthe housing portion. Additionally or alternatively, straps or otherfeatures may be used to hold other portions of the reference conductors.As shown each reference conductor includes straps 430A and 430B. Straps430A include tabs while straps 430B include openings adapted to receivethose tabs. Here reference conductors 320A and 320B have the same shape,and may be made with the same tooling, but are mounted on oppositesurfaces of the pin module 300. As a result, a tab 430A of one referenceconductor aligns with a tab 430B of the opposing reference conductorsuch that the tab 430A and the tab 430B interlock and hold the referenceconductors in place. These tabs may engage in an opening 448 in theinsulative member, which may further aid in holding the referenceconductors in a desired orientation relative to signal conductors 314Aand 314B in pin module 300.

FIG. 4 further reveals a tapered surface 450 of the insulative member410. In this embodiment surface 450 is tapered with respect to the axisof the signal conductor pair formed by signal conductors 314A and 314B.Surface 450 is tapered in the sense that it is closer to the axis of thesignal conductor pair closer to the distal ends of the mating contactportions and further from the axis further from the distal ends. In theembodiment illustrated, pin module 300 is symmetrical with respect tothe axis of the signal conductor pair and a tapered surface 450 isformed adjacent each of the signal conductors 314A and 314B.

In accordance with some embodiments, some or all of the adjacentsurfaces in mating connectors may be tapered. Accordingly, though notshown in FIG. 4, surfaces of the insulative portions of daughtercardconnector 600 that are adjacent to tapered surfaces 450 may be taperedin a complementary fashion such that the surfaces from the matingconnectors conform to one another when the connectors are in thedesigned mating positions.

Tapered surfaces in the mating interfaces may avoid abrupt changes inimpedance as a function of connector separation. Accordingly, othersurfaces designed to be adjacent a mating connector may be similarlytapered. FIG. 4 shows such tapered surfaces 452. As shown, taperedsurfaces 452 are between signal conductors 314A and 314B. Surfaces 450and 452 cooperate to provide a taper on the insulative portions on bothsides of the signal conductors.

FIG. 5 shows further detail of pin module 300. Here, the signalconductors are shown separated from the pin module. FIG. 5 illustratesthe signal conductors before being over molded by insulative portions orotherwise being incorporated into a pin module 300. However, in someembodiments, the signal conductors may be held together by a carrierstrip or other suitable support mechanism, not shown in FIG. 5, beforebeing assembled into a module.

In the illustrated embodiment, the signal conductors 314A and 314B aresymmetrical with respect to an axis 500 of the signal conductor pair.Each has a mating contact portion, 510A or 510B shaped as a pin. Eachalso has an intermediate portion 512A or 512B, and 514A or 514B. Here,different widths are provided to provide for matching impedance to amating connector and a printed circuit board, despite differentmaterials or construction techniques in each. A transition region may beincluded, as illustrated, to provide a gradual transition betweenregions of different width. Contact tails 516A or 516B may also beincluded.

In the embodiment illustrated, intermediate portions 512A, 512B, 514Aand 514B may be flat, with broadsides and narrower edges. The signalconductors of the pairs are, in the embodiment illustrated, alignededge-to-edge and are thus configured for edge coupling. In otherembodiments, some or all of the signal conductor pairs may alternativelybe broadside coupled.

Mating contact portions may be of any suitable shape, but in theembodiment illustrated, they are cylindrical. The cylindrical portionsmay be formed by rolling portions of a sheet of metal into a tube or inany other suitable way. Such a shape may be created, for example, bystamping a shape from a sheet of metal that includes the intermediateportions. A portion of that material may be rolled into a tube toprovide the mating contact portion. Alternatively or additionally, awire or other cylindrical element may be flattened to form theintermediate portions, leaving the mating contact portions cylindrical.One or more openings (not numbered) may be formed in the signalconductors. Such openings may ensure that the signal conductors aresecurely engaged with the insulative member 410.

Turning to FIG. 6, further details of daughtercard connector 600 areshown in a partially exploded view. As shown, connector 600 includesmultiple wafers 700A held together in a side-by-side configuration.Here, eight wafers, corresponding to the eight columns of pin modules inbackplane connector 200, are shown. However, as with backplane connector200, the size of the connector assembly may be configured byincorporating more rows per wafer, more wafers per connector or moreconnectors per interconnection system.

Conductive elements within the wafers 700A may include mating contactportions and contact tails. Contact tails 610 are shown extending from asurface of connector 600 adapted for mounting against a printed circuitboard. In some embodiments, contact tails 610 may pass through a member630. Member 630 may include insulative, lossy and/or conductiveportions. In some embodiments, contact tails associated with signalconductors may pass through insulative portions of member 630. Contacttails associated with reference conductors may pass through lossy orconductive portions of member 630. In some embodiments, the lossy orconductive portions may be compliant, enabling those portions to conformto and press against ground conductors within the connector and groundpads on a printed circuit board to which the connector is mounted,improving the shielding capabilities of member 630 at the mountinginterface of the connector.

Mating contact portions of the wafers 700A are held in a front housingportion 640. The front housing portion may be made of any suitablematerial, which may be insulative, lossy or conductive or may includeany suitable combination or such materials. For example the fronthousing portion may be molded from a filled, lossy material or may beformed from a conductive material, using materials and techniquessimilar to those described above for the housing walls 226. As shown,the wafers are assembled from modules 810A, 810B, 810C and 810D (FIG.8), each with a pair of signal conductors surrounded by referenceconductors. In the embodiment illustrated, front housing portion 640 hasmultiple passages, each positioned to receive one such pair of signalconductors and associated reference conductors. However, it should beappreciated that each module might contain a single signal conductor ormore than two signal conductors.

FIG. 7 illustrates a wafer 700. Multiple such wafers may be alignedside-by-side and held together with one or more support members, or inany other suitable way, to form a daughtercard connector. In theembodiment illustrated, wafer 700 is formed from multiple modules 810A,810B, 810C and 810D. The modules are aligned to form a column of matingcontact portions along one edge of wafer 700 and a column of contacttails along another edge of wafer 700. In the embodiment in which thewafer is designed for use in a right angle connector, as illustrated,those edges are perpendicular.

In the embodiment illustrated, each of the modules includes referenceconductors that at least partially enclose the signal conductors. Thereference conductors may similarly have mating contact portions andcontact tails.

The modules may be held together in any suitable way. For example, themodules may be held within a housing, which in the embodimentillustrated is formed with members 900A and 900B. Members 900A and 900Bmay be formed separately and then secured together, capturing modules810A . . . 810D between them. Members 900A and 900B may be held togetherin any suitable way, such as by attachment members that form aninterference fit or a snap fit. Alternatively or additionally, adhesive,welding or other attachment techniques may be used.

Members 900A and 900B may be formed of any suitable material. Thatmaterial may be an insulative material. Alternatively or additionally,that material may be or may include portions that are lossy orconductive. Members 900A and 900B may be formed, for example, by moldingsuch materials into a desired shape. Alternatively, members 900A and900B may be formed in place around modules 810A . . . 810D, such as viaan insert molding operation. In such an embodiment, it is not necessarythat members 900A and 900B be formed separately. Rather, a housingportion to hold modules 810A . . . 810D may be formed in one operation.

FIG. 8 shows modules 810A . . . 810D without members 900A and 900B. Inthis view, the reference conductors are visible. Signal conductors (notvisible in FIG. 8) are enclosed within the reference conductors, forminga waveguide structure. Each waveguide structure includes a contact tailregion 820, an intermediate region 830 and a mating contact region 840.Within the mating contact region 840 and the contact tail region 820,the signal conductors are positioned edge to edge. Within theintermediate region 830, the signal conductors are positioned forbroadside coupling. Transition regions 822 and 842 are provided totransition between the edge coupled orientation and the broadsidecoupled orientation.

The transition regions 822 and 842 in the reference conductors maycorrespond to transition regions in signal conductors, as describedbelow. In the illustrated embodiment, reference conductors form anenclosure around the signal conductors. A transition region in thereference conductors, in some embodiments, may keep the spacing betweenthe signal conductors and reference conductors generally uniform overthe length of the signal conductors. Thus, the enclosure formed by thereference conductors may have different widths in different regions.

The reference conductors provide shielding coverage along the length ofthe signal conductors. As shown, coverage is provided over substantiallyall of the length of the signal conductors, with coverage in the matingcontact portion and the intermediate portions of the signal conductors.The contact tails are shown exposed so that they can make contact withthe printed circuit board. However, in use, these mating contactportions will be adjacent ground structures within a printed circuitboard such that being exposed as shown in FIG. 8 does not detract fromshielding coverage along substantially all of the length of the signalconductor. In some embodiments, mating contact portions might also beexposed for mating to another connector. Accordingly, in someembodiments, shielding coverage may be provided over more than 80%, 85%,90% or 95% of the intermediate portion of the signal conductors.Similarly shielding coverage may also be provided in the transitionregions, such that shielding coverage may be provided over more than80%, 85%, 90% or 95% of the combined length of the intermediate portionand transition regions of the signal conductors. In some embodiments, asillustrated, the mating contact regions and some or all of the contacttails may also be shielded, such that shielding coverage may be, invarious embodiments, over more than 80%, 85%, 90% or 95% of the lengthof the signal conductors.

In the embodiment illustrated, a waveguide-like structure formed by thereference conductors has a wider dimension in the column direction ofthe connector in the contact tail regions 820 and the mating contactregion 840 to accommodate for the wider dimension of the signalconductors being side-by-side in the column direction in these regions.In the embodiment illustrated, contact tail regions 820 and the matingcontact region 840 of the signal conductors are separated by a distancethat aligns them with the mating contacts of a mating connector orcontact structures on a printed circuit board to which the connector isto be attached.

These spacing requirements mean that the waveguide will be wider in thecolumn dimension than it is in the transverse direction, providing anaspect ratio of the waveguide in these regions that may be at least 2:1,and in some embodiments may be on the order of at least 3:1. Conversely,in the intermediate region 830, the signal conductors are oriented withthe wide dimension of the signal conductors overlaid in the columndimension, leading to an aspect ratio of the waveguide that may be lessthan 2:1, and in some embodiments may be less than 1.5:1 or on the orderof 1:1.

With this smaller aspect ratio, the largest dimension of the waveguidein the intermediate region 830 will be smaller than the largestdimension of the waveguide in regions 830 and 840. Because the lowestfrequency propagated by a waveguide is inversely proportional to thelength of its shortest dimension, the lowest frequency mode ofpropagation that can be excited in intermediate region 830 is higherthan can be excited in contact tail regions 820 and the mating contactregion 840. The lowest frequency mode that can be excited in thetransition regions will be intermediate between the two. Because thetransition from edge coupled to broadside coupling has the potential toexcite undesired modes in the waveguides, signal integrity may beimproved if these modes are at higher frequencies than the intendedoperating range of the connector, or at least are as high as possible.

These regions may be configured to avoid mode conversion upon transitionbetween coupling orientations, which would excite propagation ofundesired signals through the waveguides. For example, as shown below,the signal conductors may be shaped such that the transition occurs inthe intermediate region 830 or the transition regions 822 and 842, orpartially within both. Additionally or alternatively, the modules may bestructured to suppress undesired modes excited in the waveguide formedby the reference conductors, as described in greater detail below.

Though the reference conductors may substantially enclose each pair, itis not a requirement that the enclosure be without openings.Accordingly, in embodiments shaped to provide rectangular shielding, thereference conductors in the intermediate regions may be aligned with atleast portions of all four sides of the signal conductors. The referenceconductors may combine for example to provide 360 degree coverage aroundthe pair of signal conductors. Such coverage may be provided, forexample, by overlapping or physically contact reference conductors. Inthe illustrated embodiment, the reference conductors are U-shaped shellsand come together to form an enclosure.

Three hundred sixty degree coverage may be provided regardless of theshape of the reference conductors. For example, such coverage may beprovided with circular or elliptical reference conductors or referenceconductors of any other suitable shape. However, it is not a requirementthat the coverage be complete. The coverage, for example, may have anangular extent in the range between about 270 and 365 degrees. In someembodiments, the coverage may be in the range of about 340 to 360degrees. Such coverage may be achieved for example, by slots or otheropenings in the reference conductors.

In some embodiments, the shielding coverage may be different indifferent regions. In the transition regions, the shielding coverage maybe greater than in the intermediate regions. In some embodiments, theshielding coverage may have an angular extent of greater than 355degrees, or even in some embodiments 360 degrees, resulting from directcontact, or even overlap, in reference conductors in the transitionregions even if less shielding coverage is provided in the transitionregions.

Fully enclosing a signal pair in reference conductors in theintermediate regions may create effects that undesirably impact signalintegrity, particularly when used in connection with a transitionbetween edge coupling and broadside coupling within a module. Thereference conductors surrounding the signal pair may form a waveguide.Signals on the pair, and particularly within a transition region betweenedge coupling and broadside coupling, may cause energy from thedifferential mode of propagation between the edges to excite signalsthat can propagate within the waveguide. In accordance with someembodiments, one or more techniques to avoid exciting these undesiredmodes, or to suppress them if they are excited, may be used.

Some techniques that may be used to increase the frequency that willexcite the undesired modes. In the embodiment illustrated, the referenceconductors may be shaped to leave openings 832. These openings may be inthe narrower wall of the enclosure. However, in embodiments in whichthere is a wider wall, the openings may be in the wider wall. In theembodiment illustrated, openings 832 run parallel to the intermediateportions of the signal conductors and are between the signal conductorsthat form a pair. These slots lower the angular extent of the shielding,such that, adjacent the broadside coupled intermediate portions of thesignal conductors, the angular extent of the shielding may be less than360 degrees. It may, for example, be in the range of 355 of less. Inembodiments in which members 900A and 900B are formed by over moldinglossy material on the modules, lossy material may be allowed to fillopenings 832, with or without extending into the inside of thewaveguide, which may suppress propagation of undesired modes of signalpropagation, that can decrease signal integrity.

In the embodiment illustrated in FIG. 8, openings 832 are slot shaped,effectively dividing the shielding in half in intermediate region 830.The lowest frequency that can be excited in a structure serving as awaveguide, as is the effect of the reference conductors thatsubstantially surround the signal conductors as illustrated in FIG. 8,is inversely proportional to the dimensions of the sides. In someembodiments, the lowest frequency waveguide mode that can be excited isa TEM mode. Effectively shortening a side by incorporating slot-shapedopening 832, raises the frequency of the TEM mode that can be excited. Ahigher resonant frequency can mean that less energy within the operatingfrequency range of the connector is coupled into undesired propagationwithin the waveguide formed by the reference conductors, which improvessignal integrity.

In region 830, the signal conductors of a pair are broadside coupled andthe openings 832, with or without lossy material in them, may suppressTEM common modes of propagation. While not being bound by any particulartheory of operation, the inventors theorize that openings 832, incombination with an edge coupled to broadside coupled transition, aidsin providing a balanced connector suitable for high frequency operation.

FIG. 9 illustrates a member 900, which may be a representation of member900A or 900B. As can be seen, member 900 is formed with channels 910A .. . 910D shaped to receive modules 810A . . . 810D shown in FIG. 8. Withthe modules in the channels, member 900A may be secured to member 900B.In the illustrated embodiment, attachment of members 900A and 900B maybe achieved by posts, such as post 920, in one member, passing through ahole, such as hole 930, in the other member. The post may be welded orotherwise secured in the hole. However, any suitable attachmentmechanism may be used.

Members 900A and 900B may be molded from or include a lossy material.Any suitable lossy material may be used for these and other structuresthat are “lossy.” Materials that conduct, but with some loss, ormaterial which by another physical mechanism absorbs electromagneticenergy over the frequency range of interest are referred to hereingenerally as “lossy” materials. Electrically lossy materials can beformed from lossy dielectric and/or poorly conductive and/or lossymagnetic materials. Magnetically lossy material can be formed, forexample, from materials traditionally regarded as ferromagneticmaterials, such as those that have a magnetic loss tangent greater thanapproximately 0.05 in the frequency range of interest. The “magneticloss tangent” is the ratio of the imaginary part to the real part of thecomplex electrical permeability of the material. Practical lossymagnetic materials or mixtures containing lossy magnetic materials mayalso exhibit useful amounts of dielectric loss or conductive losseffects over portions of the frequency range of interest. Electricallylossy material can be formed from material traditionally regarded asdielectric materials, such as those that have an electric loss tangentgreater than approximately 0.05 in the frequency range of interest. The“electric loss tangent” is the ratio of the imaginary part to the realpart of the complex electrical permittivity of the material.Electrically lossy materials can also be formed from materials that aregenerally thought of as conductors, but are either relatively poorconductors over the frequency range of interest, contain conductiveparticles or regions that are sufficiently dispersed that they do notprovide high conductivity or otherwise are prepared with properties thatlead to a relatively weak bulk conductivity compared to a good conductorsuch as copper over the frequency range of interest.

Electrically lossy materials typically have a bulk conductivity of about1 Siemen/meter to about 10,000 Siemens/meter and preferably about 1Siemen/meter to about 5,000 Siemens/meter. In some embodiments materialwith a bulk conductivity of between about 10 Siemens/meter and about 200Siemens/meter may be used. As a specific example, material with aconductivity of about 50 Siemens/meter may be used. However, it shouldbe appreciated that the conductivity of the material may be selectedempirically or through electrical simulation using known simulationtools to determine a suitable conductivity that provides a suitably lowcrosstalk with a suitably low signal path attenuation or insertion loss.

Electrically lossy materials may be partially conductive materials, suchas those that have a surface resistivity between 1 Ω/square and 100,000Ω/square. In some embodiments, the electrically lossy material has asurface resistivity between 10 Ω/square and 1000 Ω/square. As a specificexample, the material may have a surface resistivity of between about 20Ω/square and 80 Ω/square.

In some embodiments, electrically lossy material is formed by adding toa binder a filler that contains conductive particles. In such anembodiment, a lossy member may be formed by molding or otherwise shapingthe binder with filler into a desired form. Examples of conductiveparticles that may be used as a filler to form an electrically lossymaterial include carbon or graphite formed as fibers, flakes,nanoparticles, or other types of particles. Metal in the form of powder,flakes, fibers or other particles may also be used to provide suitableelectrically lossy properties. Alternatively, combinations of fillersmay be used. For example, metal plated carbon particles may be used.Silver and nickel are suitable metal plating for fibers. Coatedparticles may be used alone or in combination with other fillers, suchas carbon flake. The binder or matrix may be any material that will set,cure, or can otherwise be used to position the filler material. In someembodiments, the binder may be a thermoplastic material traditionallyused in the manufacture of electrical connectors to facilitate themolding of the electrically lossy material into the desired shapes andlocations as part of the manufacture of the electrical connector.Examples of such materials include liquid crystal polymer (LCP) andnylon. However, many alternative forms of binder materials may be used.Curable materials, such as epoxies, may serve as a binder.Alternatively, materials such as thermosetting resins or adhesives maybe used.

Also, while the above described binder materials may be used to createan electrically lossy material by forming a binder around conductingparticle fillers, the invention is not so limited. For example,conducting particles may be impregnated into a formed matrix material ormay be coated onto a formed matrix material, such as by applying aconductive coating to a plastic component or a metal component. As usedherein, the term “binder” encompasses a material that encapsulates thefiller, is impregnated with the filler or otherwise serves as asubstrate to hold the filler.

Preferably, the fillers will be present in a sufficient volumepercentage to allow conducting paths to be created from particle toparticle. For example, when metal fiber is used, the fiber may bepresent in about 3% to 40% by volume. The amount of filler may impactthe conducting properties of the material.

Filled materials may be purchased commercially, such as materials soldunder the trade name Celestran® by Celanese Corporation which can befilled with carbon fibers or stainless steel filaments. A lossymaterial, such as lossy conductive carbon filled adhesive preform, suchas those sold by Techfilm of Billerica, Mass., US may also be used. Thispreform can include an epoxy binder filled with carbon fibers and/orother carbon particles. The binder surrounds carbon particles, which actas a reinforcement for the preform. Such a preform may be inserted in aconnector wafer to form all or part of the housing. In some embodiments,the preform may adhere through the adhesive in the preform, which may becured in a heat treating process. In some embodiments, the adhesive maytake the form of a separate conductive or non-conductive adhesive layer.In some embodiments, the adhesive in the preform alternatively oradditionally may be used to secure one or more conductive elements, suchas foil strips, to the lossy material.

Various forms of reinforcing fiber, in woven or non-woven form, coatedor non-coated may be used. Non-woven carbon fiber is one suitablematerial. Other suitable materials, such as custom blends as sold by RTPCompany, can be employed, as the present invention is not limited inthis respect.

In some embodiments, a lossy member may be manufactured by stamping apreform or sheet of lossy material. For example, an insert may be formedby stamping a preform as described above with an appropriate pattern ofopenings. However, other materials may be used instead of or in additionto such a preform. A sheet of ferromagnetic material, for example, maybe used.

However, lossy members also may be formed in other ways. In someembodiments, a lossy member may be formed by interleaving layers oflossy and conductive material such as metal foil. These layers may berigidly attached to one another, such as through the use of epoxy orother adhesive, or may be held together in any other suitable way. Thelayers may be of the desired shape before being secured to one anotheror may be stamped or otherwise shaped after they are held together.

FIG. 10 shows further details of construction of a wafer module 1000.Module 1000 may be representative of any of the modules in a connector,such as any of the modules 810A . . . 810D shown in FIGS. 7-8. Each ofthe modules 810A . . . 810D may have the same general construction, andsome portions may be the same for all modules. For example, the contacttail regions 820 and mating contact regions 840 may be the same for allmodules. Each module may include an intermediate portion region 830, butthe length and shape of the intermediate portion region 830 may varydepending on the location of the module within the wafer.

In the embodiment illustrated, module 1000 includes a pair of signalconductors 1310A and 1310B (FIG. 13) held within an insulative housingportion 1100. Insulative housing portion 1100 is enclosed, at leastpartially, by reference conductors 1010A and 1010B. This subassembly maybe held together in any suitable way. For example, reference conductors1010A and 1010B may have features that engage one another. Alternativelyor additionally, reference conductors 1010A and 1010B may have featuresthat engage insulative housing portion 1100. As yet another example, thereference conductors may be held in place once members 900A and 900B aresecured together as shown in FIG. 7.

The exploded view of FIG. 10 reveals that mating contact region 840includes subregions 1040 and 1042. Subregion 1040 includes matingcontact portions of module 1000. When mated with a pin module 300,mating contact portions from the pin module will enter subregion 1040and engage the mating contact portions of module 1000. These componentsmay be dimensioned to support a “functional mating range,” such that, ifthe module 300 and module 1000 are fully pressed together, the matingcontact portions of module 1000 will slide along the pins from pinmodule 300 by the “functional mating range” distance during mating.

The impedance of the signal conductors in subregion 1040 will be largelydefined by the structure of module 1000. The separation of signalconductors of the pair as well as the separation of the signalconductors from reference conductors 1010A and 1010B will set theimpedance. The dielectric constant of the material surrounding thesignal conductors, which in this embodiment is air, will also impact theimpedance. In accordance with some embodiments, design parameters ofmodule 1000 may be selected to provide a nominal impedance within region1040. That impedance may be designed to match the impedance of otherportions of module 1000, which in turn may be selected to match theimpedance of a printed circuit board or other portions of theinterconnection system such that the connector does not create impedancediscontinuities.

If the modules 300 and 1000 are in their nominal mating position, whichin this embodiment is fully pressed together, the pins will be withinmating contact portions of the signal conductors of module 1000. Theimpedance of the signal conductors in subregion 1040 will still bedriven largely by the configuration of subregion 1040, providing amatched impedance to the rest of module 1000.

A subregion 340 (FIG. 3) may exist within pin module 300. In subregion340, the impedance of the signal conductors will be dictated by theconstruction of pin module 300. The impedance will be determined by theseparation of signal conductors 314A and 314B as well as theirseparation from reference conductors 320A and 320B. The dielectricconstant of insulative portion 410 may also impact the impedance.Accordingly, these parameters may be selected to provide, withinsubregion 340, an impedance, which may be designed to match the nominalimpedance in subregion 1040.

The impedance in subregions 340 and 1040, being dictated by constructionof the modules, is largely independent of any separation between themodules during mating. However, modules 300 and 1000 have, respectively,subregions 342 and 1042 that interact with components from the matingmodule that could influence impedance. Because the positioning of thesecomponents could influence impedance, the impedance could vary as afunction of separation of the mating modules. In some embodiments, thesecomponents are positioned to reduce changes of impedance, regardless ofseparation distance, or to reduce the impact of changes of impedance bydistributing the change across the mating region.

When pin module 300 is pressed fully against module 1000, the componentsin subregions 342 and 1042 may combine to provide the nominal matingimpedance. Because the modules are designed to provide a functionalmating range, signal conductors within pin module 300 and module 1000may mate, even if those modules are separated by an amount that equalsthe functional mating range. However, that separation between themodules can lead to changes in impedance, relative to the nominal value,at one or more places along the signal conductors in the mating region.Appropriate shape and positioning of these members can reduce thatchange or reduce the effect of the change by distributing it overportions of the mating region.

In the embodiments illustrated in FIG. 3 and FIG. 10, subregion 1042 isdesigned to overlap pin module 300 when module 1000 is pressed fullyagainst pin module 300. Projecting insulative members 1042A and 1042Bare sized to fit within spaces 342A and 342B, respectively. With themodules pressed together, the distal ends of insulative members 1042Aand 1042B press against surfaces 450 (FIG. 4). Those distal ends mayhave a shape complementary to the taper of surfaces 450 such thatinsulative members 1042A and 1042B fill spaces 342A and 342B,respectively. That overlap creates a relative position of signalconductors, dielectric, and reference conductors that may approximatethe structure within subregion 340. These components may be sized toprovide the same impedance as in subregion 340 when modules 300 and 1000are fully pressed together. When the modules are fully pressed together,which in this example is the nominal mating position, the signalconductors will have the same impedance across the mating region made upby subregions 340, 1040 and where subregions 342 and 1042 overlap.

These components also may be sized and may have material properties thatprovide impedance control as a function of separation of modules 300 and1000. Impedance control may be achieved by providing approximately thesame impedance through subregions 342 and 1042, even if those subregionsdo not fully overlap, or by providing gradual impedance transitions,regardless of separation of the modules.

In the illustrated embodiment, this impedance control is provided inpart by projecting insulative members 1042A and 1042B, which fully orpartially overlap module 300, depending on separation between modules300 and 1000. These projecting insulative members can reduce themagnitude of changes in relative dielectric constant of materialsurrounding pins from pin module 300. Impedance control is also providedby projections 1020A and 1022A and 1020B and 1022B in the referenceconductors 1010A and 1010B. These projections impact the separation, ina direction perpendicular to the axis of the signal conductor pair,between portions of the signal conductor pair and the referenceconductors 1010A and 1010B. This separation, in combination with othercharacteristics, such as the width of the signal conductors in thoseportions, may control the impedance in those portions such that itapproximates the nominal impedance of the connector or does not changeabruptly in a way that may cause signal reflections. Other parameters ofeither or both mating modules may be configured for such impedancecontrol.

Turning to FIG. 11, further details of exemplary components of a module1000 are illustrated. FIG. 11 is an exploded view of module 1000,without reference conductors 1010A and 1010B shown. Insulative housingportion 1100 is, in the illustrated embodiment, made of multiplecomponents that cooperate to fix the position of the signal conductors.Central member 1110 may be molded from insulative material. In theillustrated embodiment, central member 1110 includes two grooves 1212Aand 1212B into which conductive elements 1310A and 1310B, which in theillustrated embodiment form a pair of signal conductors, may beinserted.

Covers 1112 and 1114 may be attached to opposing sides of central member1110. Covers 1112 and 1114 may aid in holding conductive elements 1310Aand 1310B within grooves 1212A and 1212B and with a controlledseparation from reference conductors 1010A and 1010B. In the embodimentillustrated, covers 1112 and 1114 may be formed of the same material ascentral member 1110. However, it is not a requirement that the materialsbe the same, and in some embodiments, different materials may be used,such as to provide different relative dielectric constants in differentregions to provide a desired impedance of the signal conductors.

In the embodiment illustrated, grooves 1212A and 1212B are configured tohold a pair of signal conductors for edge coupling at the contact tailsand mating contact portions. Over a substantial portion of theintermediate portions of the signal conductors, the pair is held forbroadside coupling. To transition between edge coupling at the ends ofthe signal conductors to broadside coupling in the intermediateportions, a transition region may be included in the signal conductors.Grooves in central member 1110 may be shaped to provide the transitionregion in the signal conductors. Projections 1122, 1124, 1126 and 1128on covers 1112 and 1114 may press the conductive elements againstcentral portion 1110 in these transition regions.

In the embodiment illustrated in FIG. 11, it can be seen that thetransition between broadside and edge coupling occurs over a region1150. At one end of this region, the signal conductors are alignededge-to-edge in the column direction in a plane parallel to the columndirection. Traversing region 1150 in towards the intermediate portion,the signal conductors jog in opposite directions perpendicular to thatplane and jog towards each other in directions parallel to that plane.As a result, at the end of region 1150, the signal conductors are inseparate planes parallel to the column direction. The intermediateportions of the signal conductors are aligned in a directionperpendicular to those planes.

Region 1150 includes the transition region, such as 822 or 842 where thewaveguide formed by the reference conductor transitions from its widestdimension to the narrower dimension of the intermediate portion, plus aportion of the narrower intermediate region 830. As a result, at least aportion of the waveguide formed by the reference conductors in thisregion 1150 has a widest dimension of W, the same as in the intermediateregion 830. Having at least a portion of the physical transition in anarrower part of the waveguide reduces undesired coupling of energy intowaveguide modes of propagation.

Having full 360 degree shielding of the signal conductors in region 1150may also reduce coupling of energy into undesired waveguide modes ofpropagation. Accordingly, openings 832 do not extend into region 1150 inthe embodiment illustrated.

FIG. 12 shows further detail of a module 1000. In this view, conductiveelements 1310A and 1310B are shown separated from central member 1110.For clarity, covers 1112 and 1114 are not shown. Transition region 1312Abetween contact tail 1330A and intermediate portion 1314A is visible inthis view. Similarly, transition region 1316A between intermediateportion 1314A and mating contact portion 1318A is also visible. Similartransition regions 1312 B and 1316B are visible for conductive element1310B, allowing for edge coupling at contact tails 1330B and matingcontact portions 1318B and broadside coupling at intermediate portion1314B.

The mating contact portions 1318A and 1318 B may be formed from the samesheet of metal as the conductive elements. However, it should beappreciated that, in some embodiments, conductive elements may be formedby attaching separate mating contact portions to other conductors toform the intermediate portions. For example, in some embodiments,intermediate portions may be cables such that the conductive elementsare formed by terminating the cables with mating contact portions.

In the embodiment illustrated, the mating contact portions are tubular.Such a shape may be formed by stamping the conductive element from asheet of metal and then rolling the mating contact portions into atubular shape. The circumference of the tube may be large enough toaccommodate a pin from a mating pin module, but may conform to the pin.The tube may be split into two or more segments, forming compliantbeams. Two such beams are shown in FIG. 12. Bumps or other projectionsmay be formed in distal portions of the beams, creating contactsurfaces. Those contact surfaces may be coated with gold or otherconductive, ductile material to enhance reliability of an electricalcontact.

When conductive elements 1310A and 1310B are mounted in central member1110, mating contact portions 1318A and 1318B fit within openings 1220A1220B. The mating contact portions are separated by wall 1230. Thedistal ends 1320A and 1320B of mating contact portions 1318A and 1318 Bmay be aligned with openings, such as opening 1222B, in platform 1232.These openings may be positioned to receive pins from the mating pinmodule 300. Wall 1230, platform 1232 and insulative projecting members1042A and 1042B may be formed as part of portion 1110, such as in onemolding operation. However, any suitable technique may be used to formthese members.

FIG. 12 shows a further technique that may be used, instead of or inaddition to techniques described above, for reducing energy in undesiredmodes of propagation within the waveguides formed by the referenceconductors in transition regions 1150. Conductive or lossy material maybe integrated into each module so as to reduce excitation of undesiredmodes or to damp undesired modes. FIG. 12, for example, shows lossyregion 1215. Lossy region 1215 may be configured to fall along thecenter line between signal conductors 1310A and 1310B in some or all ofregion 1150. Because signal conductors 1310A and 1310B jog in differentdirections through that region to implement the edge to broadsidetransition, lossy region 1215 may not be bounded by surfaces that areparallel or perpendicular to the walls of the waveguide formed by thereference conductors. Rather, it may be contoured to provide surfacesequidistant from the edges of the signal conductors 1310A and 1310B asthey twist through region 1150. Lossy region 1215 may be electricallyconnected to the reference conductors in some embodiments. However, inother embodiments, the lossy region 1215 may be floating.

Though illustrated as a lossy region 1215, a similarly positionedconductive region may also reduce coupling of energy into undesiredwaveguide modes that reduce signal integrity. Such a conductive region,with surfaces that twist through region 1150, may be connected to thereference conductors in some embodiments. While not being bound by anyparticular theory of operation, a conductor, acting as a wall separatingthe signal conductors and as such twists to follow the twists of thesignal conductors in the transition region, may couple ground current tothe waveguide in such a way as to reduce undesired modes. For example,the current may be coupled to flow in a differential mode through thewalls of the reference conductors parallel to the broadside coupledsignal conductors, rather than excite common modes.

FIG. 13 shows in greater detail the positioning of conductive members1310A and 1310B, forming a pair 1300 of signal conductors. In theembodiment illustrated, conductive members 1310A and 1310B each haveedges and broader sides between those edges. Contact tails 1330A and1330B are aligned in a column 1340. With this alignment, edges ofconductive elements 1310A and 1310B face each other at the contact tails1330A and 1330B. Other modules in the same wafer will similarly havecontact tails aligned along column 1340. Contact tails from adjacentwafers will be aligned in parallel columns. The space between theparallel columns creates routing channels on the printed circuit boardto which the connector is attached. Mating contact portions 1318A and1318B are aligned along column 1344. Though the mating contact portionsare tubular, the portions of conductive elements 1310A and 1310B towhich mating contact portions 1318A and 1318B are attached are edgecoupled. Accordingly, mating contact portions 1318A and 1318B maysimilarly be said to be edge coupled.

In contrast, intermediate portions 1314A and 1314B are aligned withtheir broader sides facing each other. The intermediate portions arealigned in the direction of row 1342. In the example of FIG. 13,conductive elements for a right angle connector are illustrated, asreflected by the right angle between column 1340, representing points ofattachment to a daughtercard, and column 1344, representing locationsfor mating pins attached to a backplane connector.

In a conventional right angle connector in which edge coupled pairs areused within a wafer, within each pair the conductive element in theouter row at the daughtercard is longer. In FIG. 13, conductive element1310B is attached at the outer row at the daughtercard. However, becausethe intermediate portions are broadside coupled, intermediate portions1314A and 1314B are parallel throughout the portions of the connectorthat traverse a right angle, such that neither conductive element is inan outer row. Thus, no skew is introduced as a result of differentelectrical path lengths.

Moreover, in FIG. 13, a further technique for avoiding skew isintroduced. While the contact tail 1330B for conductive element 1310B isin the outer row along column 1340, the mating contact portion ofconductive element 1310B (mating contact portion 1318 B) is at theshorter, inner row along column 1344. Conversely, contact tail 1330Aconductive element 1310A is at the inner row along column 1340 butmating contact portion 1318A of conductive element 1310A is in the outerrow along column 1344. As a result, longer path lengths for signalstraveling near contact tails 1330B relative to 1330A may be offset byshorter path lengths for signals traveling near mating contact portions1318B relative to mating contact portion 1318A. Thus, the techniqueillustrated may further reduce skew.

FIGS. 14A and 14B illustrate the edge and broadside coupling within thesame pair of signal conductors. FIG. 14A is a side view, looking in thedirection of row 1342. FIG. 14B is an end view, looking in the directionof column 1344. FIGS. 14A and 14B illustrate the transition between edgecoupled mating contact portions and contact tails and broadside coupledintermediate portions.

Additional details of mating contact portions such as 1318A and 1318Bare also visible. The tubular portion of mating contact portion 1318A isvisible in the view shown in FIG. 14A and of mating contact portion1318B in the view shown in FIG. 14B. Beams, of which beams 1420 and 1422of mating contact portion 1318B are numbered, are also visible.

The inventors have recognized and appreciated that high frequencysignals being carried on the signal conductors (e.g., 1314A&B) causenon-uniformly distributed electric fields. Additionally, where theelectric field interacts with dielectric material supporting the signalconductors, substantial dielectric loss may be experienced by a highfrequency, e.g. 14, 24, or 40 GHz, signal. This dielectric loss may bemitigated by removing dielectric material near the signal conductors. Inparticular, portions of the signal conductors may be proximate toregions of higher electric field intensity, which would cause higherdielectric loss. These portions of the signal conductor may be suspendedin one or more openings in the dielectric material. The openings may bedefined by and/or abut one or more pedestals in the dielectric materialthat is coupled to the signal conductor.

FIG. 15 is a cross-sectional view of a pair 1550 of signal conductors1314A&B. FIG. 15 illustrates equipotential lines (e.g., 1552A&B) whenthe pair is excited by a low voltage differential signal, such as a 50mV signal. Each equipotential line illustrates points that have the samepotential as other points identified by the same line. For clarity, notall equipotential lines are labeled.

The intensity of the electric field surrounding either of the signalconductors 1314A&B is proportional to the gradient of the equipotentiallines, e.g. where the equipotential lines are closer together theelectric field is stronger. The inventors have recognized andappreciated that the electric fields associated with propagation of adifferential signal through a pair of signals conductors may contributeto more dielectric loss than heretofore appreciated. Dielectric lossresults from the electric field interacting with the molecules of thedielectric that may be proximate to the signal conductors 1314A&B. Whilenot being bound by any particular theory of operation, it is believedthat the electric field can polarize the molecules in the dielectric,causing them to align with the electric field. As the signals carried onthe signal conductors 1314A&B oscillate, the electric field changescorrespondingly, requiring the molecules in the dielectric to rotate tostay aligned with the electric field. The molecular motion required forthe dielectric molecules to remain aligned with the electric fieldcreated by the signal causes energy loss. As this energy is beingsupplied by the signal intended to propagate through the signalconductors 1314A&B, this dielectric loss translates into signal loss (orattenuation).

The inventors have conceived of designs that reduce this signal loss byremoving dielectric material from regions around signal conductors1314A&B where the electric field is strongest and where there wouldtherefore be the most dielectric loss. In the illustrative embodiment ofFIG. 15, regions 1556A&B contain stronger electric fields than regions1554A&B. Without being bound by any particular theory of operation, thisis believed to be due to the geometry of the signal conductor 1314Abecause the magnitude of the electric field at a point is determined inpart by the distribution of electric charge around the signal conductor1314A and the distance between the point and the charge distribution.Configuring the dielectric material to include openings proximate to theregions 1556A&B may substantially reduce dielectric loss.

It should be appreciated the electric fields around signal conductor1314B mirror those around the signal conductor 1314A and labels for theregions of higher electric field around signal conductor 1314B have beenomitted for clarity. Furthermore, the signal conductors 1314A&B areshown in a broadside arrangement, but any suitable arrangement of signalconductors (e.g., edge coupling) may be used. In other arrangements, theregions of high electric field may have different locations relative tothe signal conductors than is shown in FIG. 15. Accordingly, thelocations of regions where openings in the insulative housing areprovided may deviate from the examples given in FIGS. 16A-16C and 17-18.In some embodiments, the electric field intensity may be substantiallyimpacted by interactions between the fields of two or more signalconductors. It should also be appreciated that signal conductors withrectangular cross sections are shown, but that other suitable conductorgeometries may be utilized and be associated with regions of varyingelectric field intensity different than those shown and described.

FIG. 16A is a cross-sectional view through a connector module 1660configured to reduce dielectric loss, according to an illustrativeembodiment of the invention. The cross-section may be taken in thelocation illustrated by the line 16-16 in FIG. 8. Accordingly, the crosssection may be through the intermediate portion of the signal conductorswhere they are broadside coupled, as shown in FIG. 16A. However, thecross section of a signal module may be uniform along substantially theentire length of the signal conductors within the module. Accordingly, aconnector module may have a cross section as shown in FIG. 16A over atleast 85% of the length of the signal conductors within the module. Insome embodiments, that cross section with be over 90% or over 95% of thelength of the signal conductors within the module.

In the embodiment illustrated, module 1660 may differ from module 810Ain that it is arranged to reduce dielectric loss in the signalconductors 1314A&B by providing openings 1665A-D around areas ofrelatively intense electric fields. That configuration may be providedby using insulative members as described below in place of centralmember 1110 and covers 1112 and 1114 in each wafer module in theconnector. Module 1660 may otherwise be configured like and be used in aconnector with any or all of the features described herein.

The signal conductors 1314A&B may be any suitable signal conductors, forexample those discussed with reference to other aspects of the presentdisclosure such as FIGS. 8 and 10-15. However, in some embodiments, theopenings in the dielectric around the signal conductors enables largersignal conductors 1314A&B to be used without changing the totalimpedance of the signal conductors in the module, which reduces signalloss in the conductors. In the illustrative embodiment, the signalconductors 1314A&B are broadside coupled, but any suitable coupling orarrangement may be used. The signal conductors 1314A&B may carry anysuitable differential and/or high frequency signals, thereby creatingelectrical potentials and fields, for example as was discussed withreference to FIG. 15.

Openings 1665A-D represent space created by the insulative supportmembers (e.g., 1661 and 1667A&B), which may be filled with air or othermaterial having lower dielectric loss than the insulative materialforming the insulative members. Having an air gap around the ends of thesignal conductors 1314A&B, where the electric field caused by the signalis strongest, has been found to effectively limit the dielectric losswhile providing adequate support to stably maintain the signalconductors 1314A&B. For example, the selective positioning of theopenings 1165A-D with respect to the regions of higher electric fieldstrength caused by a 40 GHz low voltage (e.g. 50 mV) differential signalmay prevent 0.5 dB, 1 dB, 3 dB, 5 dB, or more dielectric loss that wouldoccur if the openings 1665A-D were filled with the material of centralmember 1661 and/or covers 1667A&B. In other embodiments or at otherfrequencies, such as 14 GHz, the loss may be 10-15% less with openingsthan without. The openings 1665A-D may be sized proportionally to theconductor and have square, rectangular, circular, or any other suitablegeometries. For example, the openings 1665A-D may be substantiallysquare with sides that are twice, 3×, 4×, 5× or more times the thicknessof the conductor. The openings may be sized relative to the magnitude ofthe electric field, for example to remove material from areas withelectric field intensity above a threshold. In some embodiments, theopenings 1665A-D may be porous areas in the dielectric material. In someembodiments, each of the openings 1665A-D may include several smalleropenings, such as smaller squares, slits, a collection of hollow cells,or any other suitable arrangement.

The module 1660 includes central member 1661 and covers 1667A&Bconfigured to position the signal conductors 1314A&B within the openings1665A-D. Collectively, the central member 1661 and covers 1667A&B may bereferred to as one or more insulative support members and may form astructure for holding the length of signals conductors, for example aswas discussed with reference to insulative housing portion 1100 and FIG.11. The insulative support members may be formed from any suitableinsulative material that allows the insulative support members tostructurally cooperate to align the signal conductors 1314A&B.

The central member 1661 includes pedestals 1663A&B that are configuredto support the signal conductors 1314A&B in the openings 1665A-D. In theillustrative embodiment, the pedestals 1663A-B standoff from theremainder of the central member 1661 and define the openings 1665A-D.The pedestals 1663A-D may have any suitable width for supporting thesignal conductors 1314A&B. For example, the pedestals 1663A-D have awidth that is 90%, 80%, 50%, 25% or less of the width of the signalconductors 1314A-B. In some embodiments, the signal conductors 1314A&Band the pedestals 1663A-D may be configured such that at least 10% ofthe width of each signal conductor extends into one of the openings1665A-D. In some embodiments, the pedestals 1663A&B are arranged toalign the signal conductors 1314A&B. In some embodiments, the centralmember 1661 comprises support elements within one or more portions ofthe openings 1665A-D for aligning the signal conductors 1314A&B withinthe remaining portions of the openings 1665A-D. In the configurationillustrated, pedestals 1163A and 1663B establish the spacing betweensignal conductors 1314A&B, as covers 1667A&B are configured to presssignal conductors 1314A&B against pedestals 1163A and 1663B,respectively.

The covers 1667A&B may be positioned on opposing sides of the centralmember 1661. In the embodiment illustrated, the coves 1667A&B may beformed of the same material as the central member 1661. However, it isnot a requirement that the materials be the same, and in someembodiments, different materials may be used, such as to providedifferent relative dielectric constants in different regions to providea desired impedance of the signal conductors. The pedestals 1663C&D maybe configured similarly to the pedestals 1663A&B, but this is notrequired. In some embodiments, the pedestals 1663C&D may be the same ordifferent widths and/or heights as any of the pedestals 1663A-D.

The covers 1667A&B may be configured to aid in holding the signalconductors 1314A&B between the pedestals 1663A&B of the central member1661 and the pedestals 1663C&D of the covers 1667A&B. The pedestals1663C&D may be connected to compliant portions of the covers 1667A&B.Compliance in the covers 1667A&B may allow the covers 1667A&B to pinchthe signal conductors 1314A&B while also compensating for warpage ormisalignment in the module 1660 assembly.

The insulative support members may be enclosed entirely or partially (asshown in FIG. 16A) by reference conductors 1671A&B. This assembly may beheld together in any suitable way. For example, the reference conductors1671A&B may have features that engage one another. Alternatively oradditionally, the reference conductors 1671A&B may be held in place byexterior shields and/or lossy material used in the wafer assembly.

As an example of how reference conductors 1671A&B may generate force oncovers 1667A&B, FIG. 16B shows a cross section through module 1660 in adifferent location than is shown in FIG. 16A. At the location of thecross section shown in FIG. 16B, one or both of covers 1667A&B mayinclude latching features that hold the reference conductors 1671A&Btogether. Latching features 1672A and 1672B are shown schematically. Thelatching features may be configured to place the subassembly comprisingcentral member 1661 and covers 1667A&B in compression. A sufficientnumber of latching features may be included along the length of themodule to provide the required compressive force and to hold the moduletogether. Accordingly there may be multiple such latching features alongthe length of the module.

In the illustrative embodiment of FIG. 16B, the covers 1667A&B areconnected to the reference conductors 1617A&B by standoffs 1669A-D.These standoffs 1669A-D may be configured to limit the surface area ofthe covers 1667A&B that contact the reference conductors 1671A&B. Thismay prevent over-constraining the assembly and aid in alignment. In someembodiments, the standoffs 1669A-B may be configured to kinematicallycouple with the reference conductors to exactly constrain the covers1667A&B with respect to the reference conductors 1671A&B.

In some embodiments, some portions (e.g., corners) of the covers 1667A&Bare recessed from the reference conductors 1671A&B, which createsopenings 1673A-F. The openings 1673A-F may limit dielectric loss sincethe electric field is non-zero within the reference conductors 1671A&Band may be non-negligible. Additionally, the openings 1671A-F may beadvantageous for the consistent and durable assembly of the module 1660.The openings 1673A-F may allow for variability in the stamping and/orforming of the reference conductors 1671A&B, because, without suchopenings, the inner radius of the reference conductors 1671A&B mightinterfere with the insulative support members and prevent the referenceconductors 1671A&B and/or additional shields from being pressed intoposition on and around the insulative support members.

The compressive forces, created by reference conductors 1671A&B aroundthe insulative members positions the signal conductors with respect toeach other in a vertical direction in the orientation shown in FIG. 16B.As this direction is perpendicular to the wide direction of the signalconductors and therefore the direction in which the signal conductorsare most flexible. Accordingly, the cross section of the insulativemembers is substantially the same in the cross sections of FIGS. 16A and16B. This same cross section may be maintained over all or substantiallyall of the length of the intermediate portions of the signal conductors,such as greater than 90% of the intermediate portion, or greater than95% in some embodiments.

Lateral support, positioning the signal conductors relative to eachother in a direction parallel to the wide dimension of the signalconductors, is not shown in FIGS. 16A and 16B. However, lateral supportof the intermediate portions of the signal conductors may be included atsome locations along their length. In some embodiments, lateral supportmay be provided at only locations totaling a fraction of the length ofthe openings 1665A . . . 16665D. FIG. 16C shows a cross section ofmodule 1660 at such a location. In the embodiment illustrated, lateralsupport is provided by projections 1662A . . . 1662D from the walls ofthe channels in central portion 1661 that form openings 1665A . . .16665D. Projections to provide lateral support may alternatively extendfrom covers 1667A and 1667B or any other suitable structure may be usedto provide lateral support.

In the illustrated embodiment, lateral support is not included along thefull length of the intermediate portions of signal conductors 1314A&B.In some embodiments, projections 1662A . . . 1662D may be span less than25% of the length, and in some embodiments, less than 15% or less than10%.

FIG. 17 is a cross-sectional view of a module 1760 with an alternativeconfiguration of insulative members configured to reduce dielectricloss. FIG. 17 is, like FIG. 16A, a cross section, through a portion of amodule without lateral support or latching features, but features asdescribed above in connection with FIGS. 16B and 16C, or any othersuitable structures performing the same functions, may be used with theconfiguration of FIG. 17.

In the illustrative embodiment of FIG. 17, the central member 1761 isconfigured to include pedestals 1763A-D, which create openings 1765A-F.Openings 1765A-B and 1765E-F remove dielectric material in regions 1556Aand 1556B (FIG. 15) of high electric field and reduce dielectric lossfor the same reasons as described above in connection with FIG. 16A.However, more dielectric is removed around the edges of the signalconductors in FIG. 16A, as sufficient material is removed to expose thefirst and second surfaces at the edges of the signal conductors in FIG.16A, while only one such surface on each signal conductor is exposed inFIG. 17.

In some embodiments, the pedestals 1763A-B are in contact with the endsof one side of the signal conductors 1314A&B to aid in assembly andalignment. In further embodiments, the pedestals 1763A-D are recessedinto the central member 1761. For example, the pedestals 1763A-D may berecessed by the thickness of the signal conductors 1314A&B such that theopposite surface of the signal conductors 1314A&B is substantiallyco-planar with portions of the central member 1761 that are in contactwith the covers 1767A&B. There is, nonetheless, an opening in theinsulative support between the edge of the signal conductor and the wallof central member 1761 where dielectric loss is reduced.

In the example of FIG. 17, the pedestals 1763A-D are additionallyconfigured to create an opening 1765C&D near the centers of the signalconductors 1314A&B. The openings 1765C&D, in addition to eliminatingsome dielectric loss, may mechanically aid in assembly of the module1760. For example the openings 1765C&D may compensate for warpage of theinsulative support members or the reference shields 1771A&B,additionally the openings 1765C&D may provide compliance to relieveexcess pressure on the signal conductors 1314A&B from the pedestals1763E&F. In some embodiments, the openings 1765A-F may be sized toprevent changes or variations in size (e.g., due to assembly ortemperature) from substantially changing the impedance of the module1760.

A method of manufacturing modules (e.g., 1660 and 1760) for limitingdielectric loss may include the step of positioning a central member ofan insulative support between at least two conductors. Each of the atleast two conductors include a first end and a second end and anintermediate portion connecting the first end and the second end, theintermediate portion including a first edge and a second edge and afirst side and a second side between the first edge and the second edge,the first and second sides being wider than the first and second edges.The at least two conductors may include a first conductor and a secondconductor (e.g., 1314A&B). The central member may include a firstpedestal portion and a second pedestal portion, such that the firstpedestal portion contacts the first side of the first conductor and thesecond pedestal portion contacts the first side of the second conductor.A first cover and a second cover of the insulative support may bepositioned adjacent to the first conductor and the second conductorrespectively, with each of the first and second cover includingrespective pedestal portions. The pedestal portions of the first covermay contact the second side of the first conductor and the pedestalportion of the second cover may contact the second side of the secondconductor. At least a portion of the covers and the central member maybe surrounded with one or more reference conductors.

FIG. 18 illustrates a further alternative embodiment in which a materialwith 1low dielectric loss, air in the illustrated embodiment, isselectively positioned in regions of high electric fields adjacent tosignal conductors. As in the embodiments illustrated in FIGS. 16A and17, such a configuration may be created by molding plastic supports withchannels or other structures that create openings adjacent the edges ofthe signal conductors. In FIG. 18, the signal conductors 1314A and 1314Bare configured as a broadside coupled differential pairs and supportmembers 1861 and 1867A&B are shaped with openings 1865A, 1865B, 1865Cand 1865D positioned adjacent the edges of the signal conductors.

FIG. 18 represents a cross section through a module. As described above,such a module may be formed of separate insulating support members 1861and 1867A&B with signal conductors held between support members. Thesupport members may be molded such that the illustrated cross sectionexists over substantially all of the length of the signal conductorswithin a module. However, as shown above in connection with FIGS. 16Band 16C, other cross sections may be created at intermittent locationsalong the length of signal conductors, such as in locations wherelateral supports for the signal conductors or latching of the shieldmembers is provided. As with the cross section of FIG. 16A or 17, thecross section of FIG. 18 may be created over 90%, or more, of the lengthof the signal conductors within the module.

Openings 1865A, 1865B, 1865C and 1865D in FIG. 18 are smaller thanopenings 1665A, 1665B, 1665C and 1665D and openings 1765A, 1765B, 1765Eand 1765F. Openings 1865A, 1865B, 1865C and 1865D expose an uppersurface of 1314A and 1314B adjacent the edges, even though the lowersurfaces of those conductive elements, even adjacent the edges, areresting on a plastic support. FIG. 18 illustrates that even thosesmaller openings can provide benefit. In some embodiments, a structureas in FIG. 18 may provide adequate performance and may provide anadvantage of being easy to mold.

The embodiment of FIG. 18 also does not have openings 1673A-F as in FIG.16A. Those openings are useful for providing springiness in insulativesupport members 1667A and 1667B, which aids in holding the signalconductors 1314A and 1314B firmly in place with a uniform and controlledseparation dictated by the spacing between surfaces of pedestals 1663Aand 1663B.

The embodiment of FIG. 18 has no openings between the broadsides of thesignal conductors corresponding to openings 1765C and 1765D in FIG. 17.FIG. 18 illustrates that such opening are not required to deliver lowinsertion loss. However, any of the above features could be used withthe structures illustrated in FIG. 18.

FIG. 19 is an isometric view of a wafer, partially cutaway to reveal aportion of a wafer module with edge-coupled signal conductors configuredto reduce dielectric loss, according to an illustrative embodiment. Thewafer module includes a connector module 1960 with an alternativeconfiguration of insulative members configured to reduce dielectricloss. FIG. 19 may be implemented using features as described above inconnection with FIGS. 16A-16C, 17, and 18; or any other suitablestructures performing the same functions, may be used with theconfiguration of FIG. 19. In the illustrative embodiment of FIG. 19, themodule 1960 is disposed between members 1981A and 1981B, which may belossy in some embodiments or insulative in other embodiments. The module1960 includes reference shield 1971A and 1971B, which partially surroundcovers 1967A and 1967B, which hold the signal conductors 1314A and1314B.

In the illustrative embodiment of FIG. 19, the signal conductors 1314A&Bare edge coupled, for example as was described earlier at least withreference to FIG. 5. The signal conductors are arranged to have adjacentedges and the sides are aligned. In the illustrative embodiment, thesides of the signal conductors 1314A&B are substantially co-linear. Inthe case of signal conductors with rectangular cross section, the edgesmay be considered to be the narrower portions of the exterior.

In the illustrative embodiment of FIG. 19, the insulative supportmembers includes two covers 1967A&B that are configured to includepedestals to create openings, and no distinct, central insulativesupport member is required between the two covers 1967A&B. The covers1967A&B are configured to create openings that remove dielectricmaterial in regions of high electric field and reduce dielectric lossfor the same reasons as described above in connection with FIG. 16A.Although the signal conductors 1314A&B are edge coupled, the inventorshave recognized and appreciated that regions of high electric field mayoccur as was described with reference to regions 1556A and 1556B (inFIG. 15). In particular, FIG. 19 shows dielectric is removed around theedges of the signal conductors to expose the first and second surfacesat the edges of the signal conductors 1314 A&B. In some embodiments, oneedge of each signal conductor 1314A&B is proximate to less dielectricmaterial than the other corresponding edge of the same signal conductor.In some embodiments, the areas of removed dielectric may be configuredas was discussed with reference to FIGS. 16A-C, 17, and 18, or accordingto any suitable arrangement for reducing dielectric loss.

FIG. 20A is a cross sectional view of a portion of a wafer withedge-coupled signal conductors configured to reduce dielectric loss. Inthe example of FIG. 20A, the wafer includes a connector module 2060 witha configuration of insulative members configured to reduce dielectricloss. FIG. 20A may be implemented using features as described above inconnection with FIG. 19, or any other suitable structures performing thesame functions may be used with the configuration of FIG. 20A. In theillustrative embodiment of FIG. 20A, the module 2060 is disposed betweenlossy members. The module 2060 includes reference shield 2071A and2071B, which surround covers 2067A and 2067B, which hold the signalconductors 1314A and 1314B. Cover 2067A includes standoffs 2069A-C aswell as pedestals 2063A,B,&E. Cover 2067B includes pedestals 2063C&D andstandoffs 2069D-F.

In the illustrative embodiment of FIG. 20A, the signal conductors1314A&B are edge coupled, for example as was described earlier at leastwith reference to FIG. 19. The pedestals 2063A-B are in contact with aportion of one side of the signal conductors 1314A&B and the pedestals2063C&D are in contact with portions of the opposite sides of the signalconductors 1314A&B. The projection 2063E extends between cover 2067A andcover 2067B. In some embodiments, the projection 2063E contacts thecover 2067B and spaces the insulative support members. In someembodiments, the projection 2063E does not touch the cover 2067B.

In some embodiments, the projection 2063E may be configured to contactedges of the signal conductors 1314A&B, which may provide lateralsupport for all or a portion of the signal conductors 1314A&B. In someembodiments, projections 2062A&B may provide lateral support and/oralignment for all or a portion of the signal conductors 1314A&B.Projections 2062A&B may function as was described with reference toprojections 1662A-D.

In the example of FIG. 20A, insulative support members (2067A&B) areconfigured to create openings 2073A-H and openings 2065A-D. Theseopenings, as has been described with reference to earlier FIGS. (e.g.,FIG. 17) may, in addition to eliminating some dielectric loss,mechanically aid in assembly of the waveguide 2060.

FIG. 20B is a cross sectional view of a portion of a wafer withedge-coupled signal conductors configured to reduce dielectric loss,according some embodiments. FIG. 20B shows a cross section through adifferent portion of connector module 2060 than is illustrated in FIG.20A. In the illustrated embodiment, connector module 2060 has aconfiguration of insulative members further configured to reducedielectric loss.

In contrast with the cross section illustrated in FIG. 20A, the portionof cover 2067A&B shown in FIG. 20B do not include a pedestal between thesignal conductors 1314A&B. Projections 2062A and 2062B also do notappear in this cross-section. FIG. 20A may represent a first portion ofa wafer and FIG. 20B may represent a second portion of the same wafer,displaced from the first portion along the length of the same signalconductors 1314A&B. Projections, such as projection 2063E may be presentat discontinuous locations along the length of the same signalconductors 1314A&B. Such projections may provide lateral alignment ofthe signal conductors 1314A&B. However, in order to limit dielectricloss, projection 2063E may be configured to be proximal only to one ormore portions of the length of the signal conductors 1314A&B. Forexample, projection 2063E may be configured to span less than 25% of thelength, and in some embodiments, less than 15% or less than 10%.Projections 2062A and 2062B may similarly be proximal only to one ormore portions of the length of the signal conductors 1314A&B, which maybe the same or different portions as projection 2063E.

FIGS. 21A&B show partially exploded views of a connector module (e.g.2060) with edge-coupled signal conductors. The signal conductors 1314A&Bmay be disposed between insulative support members covers 2167A&B, whichmay function as was described with reference to the insulative supportmembers in at least FIGS. 19 and 20A&B. The insulative support membersmay be surrounded by reference conductors 2171A&B, which may function aswas described with reference to any reference conductors herein.

In the configuration of FIG. 21A, it can be seen that lateral supportand positioning of the signal conductors 1314A and 1314B is provided byprojections 2162 that pass through holes in the signal conductors,rather than abut the sides of the signal conductors. Either or both ofthese mechanisms, as well as other suitable structures, may be used toposition the signal conductors within a module.

FIG. 22 shows a partially exploded view of a wafer 2290, according to anillustrative embodiment. The wafer module 2290 shown may be the same asand/or function as the wafer shown cross sectioned in FIG. 19. Multipleconnector modules, only 2260A&B are labeled for clarity, may be coveredin lossy material 2281A&B to form wafer module 2290. The connectormodules 2260A&B may function as were described with reference to atleast FIGS. 19 and 20A&B.

FIG. 23 shows a partially exploded view of a vertical connector 2300,according to an illustrative embodiment. The vertical connecter 2300 mayinclude multiple wafers, including 2390A&B. The wafers may beconstructed as was described with reference to FIG. 22. The wafers maybe assembled and configured to connect to the housing 2340, member 2330,and organizers 2392A&B. The organizers 2392A&B may be made of anysuitable material and configured to space the wafers (e.g., 2390A&B) atsuitable intervals.

Member 2330 may include insulative, lossy and/or conductive portions. Insome embodiments, contact tails associated with signal conductors in thewafers (e.g., 2390A&B) may pass through insulative portions of member2330. Contact tails associated with reference conductors may passthrough lossy or conductive portions of member 2330. In someembodiments, the lossy or conductive portions may be compliant, enablingthose portions to conform to and press against ground conductors withinthe connector 2300 and ground pads on a printed circuit board to whichthe connector 2300 is mounted, improving the shielding capabilities ofmember 2230 at the mounting interface of the connector.

Mating contact portions of the wafers (e.g., 2390A&B) are held in afront housing portion 2340. The front housing portion 2340 may be madeof any suitable material, which may be insulative, lossy or conductiveor may include any suitable combination or such materials. For examplethe front housing portion 2340 may be molded from a filled, lossymaterial or may be formed from a conductive material, using materialsand techniques similar to those described above for the housing walls226. In the embodiment illustrated, front housing portion 2340 hasmultiple passages, each positioned to receive one pair of signalconductors and associated reference conductors.

In some embodiments, pedestal portions of the insulative support areshaped to provide one or more openings in a dielectric material, and themethod of manufacturing the modules may include positioning edges of theconductors in the one or more openings. The method of manufacture mayalso include forming wafers by, at least in part, positioning multiplelossy members so that each lossy member is electrically coupled tomultiple reference conductors and aligning the plurality of wafers inparallel.

The frequency range of interest may depend on the operating parametersof the system in which such a connector is used, but may generally havean upper limit between about 10 GHz and 50 GHz, such as 25 GHz, 30 or 40GHz, although higher frequencies or lower frequencies may be of interestin some applications. Some connector designs may have frequency rangesof interest that span only a portion of this range, such as 1 to 10 GHzor 3 to 15 GHz or 5 to 35 GHz. In some embodiments, connectors may bedesigned to carry signals with frequencies of 14 GHz or 24 GHz. Theimpact of unbalanced signal pairs, and any discontinuities in theshielding at the mounting interface may be more significant at thesehigher frequencies.

The operating frequency range for an interconnection system may bedetermined based on the range of frequencies that can pass through theinterconnection with acceptable signal integrity. Signal integrity maybe measured in terms of a number of criteria that depend on theapplication for which an interconnection system is designed. Some ofthese criteria may relate to the propagation of the signal along asingle-ended signal path, a differential signal path, a hollowwaveguide, or any other type of signal path. Two examples of suchcriteria are the attenuation of a signal along a signal path or thereflection of a signal from a signal path.

Other criteria may relate to interaction of multiple distinct signalpaths. Such criteria may include, for example, near end cross talk,defined as the portion of a signal injected on one signal path at oneend of the interconnection system that is measurable at any other signalpath on the same end of the interconnection system. Another suchcriterion may be far end cross talk, defined as the portion of a signalinjected on one signal path at one end of the interconnection systemthat is measurable at any other signal path on the other end of theinterconnection system.

As specific examples, it could be required that signal path attenuationbe no more than 3 dB power loss, reflected power ratio be no greaterthan −20 dB, and individual signal path to signal path crosstalkcontributions be no greater than −50 dB. Because these characteristicsare frequency dependent, the operating range of an interconnectionsystem is defined as the range of frequencies over which the specifiedcriteria are met.

Designs of an electrical connector are described herein that improvesignal integrity for high frequency signals, such as at frequencies inthe GHz range, including up to about 25 GHz or up to about 40 GHz, up toabout 50 GHz or up to about 60 GHz or up to about 75 GHz or higher,while maintaining high density, such as with a spacing between adjacentmating contacts on the order of 3 mm or less, including center-to-centerspacing between adjacent contacts in a column of between 1 mm and 2.5 mmor between 2 mm and 2.5 mm, for example. Spacing between columns ofmating contact portions may be similar, although there is no requirementthat the spacing between all mating contacts in a connector be the same.

While a broadside-coupled configuration may be desirable for theintermediate portions of the conductive elements, a completely orpredominantly edge-coupled configuration may be adopted at a matinginterface with another connector or at an attachment interface with aprinted circuit board. Such a configuration, for example, may facilitaterouting within a printed circuit board of signal traces that connect tovias receiving contact tails from the connector.

Accordingly, the conductive elements inside the connector may havetransition regions at either or both ends. In a transition region, aconductive element may jog out of the plane parallel to the widedimension of the conductive element. In some embodiments, eachtransition region may have a jog toward the transition region of theother conductive element. In some embodiments, the conductive elementswill each jog toward the plane of the other conductive element such thatthe ends of the transition regions align in a same plane that isparallel to, but between the planes of the individual conductiveelements. To avoid contact of the transition regions, the conductiveelements may also jog away from each other in the transition regions. Asa result, the conductive elements in the transition regions may bealigned edge to edge in a plane that is parallel to, but offset from theplanes of the individual conductive elements. Such a configuration mayprovide a balanced pair over a frequency range of interest, whileproviding routing channels within a printed circuit board that support ahigh density connector or while providing mating contacts on a pitchthat facilitates manufacture of the mating contact portions.

In embodiments in which an edge-coupled configuration is employed at theintermediate portions of the signal conductors, the openings in theinsulative support members may be positioned differently than for thebroadside coupled configuration to ensure that the openings coincidewith the regions of high electric field around the signal conductors. Insome configurations, for example, the openings in the insulative supportmembers may be preferentially configured between the signal conductorsof the pair and encompassing the opposing edges of the pair, as well asportions of the first and/or second surfaces of the wide dimension ofsignal conductors adjacent those edges. In some embodiments, theportions of the first and second surfaces exposed may account forpercentages of the surface as described above, such as for example, morethan 25% or more than 50% in some embodiments. In such an embodiment,lateral support may also be provided at some locations along the lengthof the signal conductors. However, the lateral support may be betweenthe edges of the edge-coupled signal conductors.

Although details of specific configurations of conductive elements,housings, and shield members are described above, it should beappreciated that such details are provided solely for purposes ofillustration, as the concepts disclosed herein are capable of othermanners of implementation. In that respect, various connector designsdescribed herein may be used in any suitable combination, as aspects ofthe present disclosure are not limited to the particular combinationsshown in the drawings.

Having thus described several embodiments, it is to be appreciatedvarious alterations, modifications, and improvements may readily occurto those skilled in the art. Such alterations, modifications, andimprovements are intended to be within the spirit and scope of theinvention.

As one example, 50 millivolt signals were given as an example of lowvoltage differential signals. Low voltage signals may have adifferential voltage of 2 Volts or less.

Accordingly, the foregoing description and drawings are by way ofexample only.

Manufacturing techniques may also be varied. For example, embodimentsare described in which the daughtercard connector 600 is formed byorganizing a plurality of wafers onto a stiffener. It may be possiblethat an equivalent structure may be formed by inserting a plurality ofshield pieces and signal receptacles into a molded housing.

As another example, connectors are described that are formed of modules,each of which contains one pair of signal conductors. It is notnecessary that each module contain exactly one pair or that the numberof signal pairs be the same in all modules in a connector. For example,a 2-pair or 3-pair modules may be formed. Moreover, in some embodiments,a core module may be formed that has two, three, four, five, six, orsome greater number of rows in a single-ended or differential pairconfiguration. Each connector, or each wafer in embodiments in which theconnector is waferized, may include such a core module. To make aconnector with more rows than are included in the base module,additional modules (e.g., each with a smaller number of pairs such as asingle pair per module) may be coupled to the core module.

Furthermore, although many inventive aspects are shown and describedwith reference to a daughterboard connector having a right angleconfiguration, it should be appreciated that aspects of the presentdisclosure is not limited in this regard, as any of the inventiveconcepts, whether alone or in combination with one or more otherinventive concepts, may be used in other types of electrical connectors,such as backplane connectors, cable connectors, stacking connectors,mezzanine connectors, I/O connectors, chip sockets, etc.

In some embodiments, contact tails were illustrated as press fit “eye ofthe needle” compliant sections that are designed to fit within vias ofprinted circuit boards. However, other configurations may also be used,such as surface mount elements, spring contacts, solderable pins, etc.,as aspects of the present disclosure are not limited to the use of anyparticular mechanism for attaching connectors to printed circuit boards.

The present disclosure is not limited to the details of construction orthe arrangements of components set forth in the foregoing descriptionand/or the drawings. Various embodiments are provided solely forpurposes of illustration, and the concepts described herein are capableof being practiced or carried out in other ways. Also, the phraseologyand terminology used herein are for the purpose of description andshould not be regarded as limiting. The use of “including,”“comprising,” “having,” “containing,” or “involving,” and variationsthereof herein, is meant to encompass the items listed thereafter (orequivalents thereof) and/or as additional items.

What is claimed is:
 1. An electrical connector comprising: a subassemblycomprising: a central insulative portion, the central insulative portionhaving openings; cover portions disposed over the openings on oppositesides of the central insulative portion; and at least one pair ofconductors disposed in the openings and supported by the centralinsulative portion; wherein the openings are configured to provideclearances around edges of conductors of the at least one pair ofconductors.
 2. The electrical connector of claim 1, wherein theconductors of the at least one pair of conductors comprise: a first endand a second end; and an intermediate portion connecting the first endand the second end, the intermediate portion comprising a first edge anda second edge and a first side and a second side between the first edgeand the second edge, the first and second sides being wider than thefirst and second edges.
 3. The electrical connector of claim 2, whereinthe central insulative portion is configured to provide clearancesaround the first and second edges of the conductors of the at least onepair of conductors.
 4. The electrical connector of claim 2, wherein thecentral insulative portion is configured to at least partially exposethe first and second sides of the conductors within the clearances. 5.The electrical connector of claim 2, wherein the central insulativeportion is configured to support a first conductor of the at least onepair of conductors and a second conductor of the at least one pair ofconductors such that the first and second sides of the first conductorare parallel to the first and second sides of the second conductor. 6.The electrical connector of claim 2, wherein: the first ends of thefirst and second signal conductors comprise mating contact portions; thesecond ends of the first and second signal conductors comprise contacttails; and the mating contact portions and the contact tails extend fromthe support.
 7. The electrical connector of claim 1, wherein the coverportions comprise lossy or insulative material.
 8. An electricalconnector comprising: a subassembly comprising: an insulative portion,the insulative portion having openings; and at least one pair ofconductors disposed in the openings and supported by the insulativeportion; wherein: the openings are configured to provide clearancesaround edges of conductors of the at least one pair of conductors. thecentral insulative portion comprises: a first member; and a secondmember, the pair of conductors is disposed between the first member andthe second member.
 9. The electrical connector of claim 8, wherein: thefirst member comprises a first pedestal portion and a second pedestalportion, the second member comprises a third pedestal portion and afourth pedestal portion, the pair of conductors comprises a firstconductor and a second conductor, and the first pedestal portioncontacts the first side of the first conductor, the second pedestalportion contacts the first side of the second conductor, the thirdpedestal portion contacts the second side of the first conductor, andthe fourth pedestal portion contacts the second side of the secondconductor.
 10. The electrical connector of claim 9, wherein the secondedge of the first conductor is held adjacent the first edge of thesecond conductor.
 11. The electrical connector of claim 8, wherein thecentral insulative portion further comprises a third member, the thirdmember disposed between conductors of the pair of conductors.
 12. Theelectrical connector of claim 8, further comprising referenceconductors, the reference conductors disposed at least partially aroundthe central insulative portion and configured to press the first membertowards the second member such that conductors of the pair of conductorsare pinched between the first member and the second member.
 13. Theelectrical connector of claim 12, wherein the reference conductorscomprise two joined metal members that collectively encircle the firstmember and the second member of the central insulative portion.
 14. Theelectrical connector of claim 12, wherein the pair of conductors are anedge side coupled pair of signal conductors and the reference conductorsform a shield around the edge side coupled pair of signal conductors.15. An electrical connector comprising: a plurality of wafers aligned inparallel, each of the wafers comprising: a plurality of pairs ofconductors; central insulative portions configured to support a pair ofconductors of the plurality of pairs of conductors, the centralinsulative portion having openings on opposite ends and being configuredto provide clearances around edges of conductors of the pair ofconductors; and cover portions disposed on each side of the centralinsulative portion.
 16. The electrical connector of claim 15, whereinthe conductors of the plurality of pairs of conductors each comprise: afirst end and a second end; and an intermediate portion connecting thefirst end and the second end, the intermediate portion comprising afirst edge and a second edge and a first side and a second side betweenthe first edge and the second edge, the first and second sides beingwider than the first and second edges, wherein the central insulativeportions are configured to provide clearances around the first andsecond edges of conductors of the plurality of pairs of conductors. 17.The electrical connector of claim 16, wherein the central insulativeportions comprise: a first member; and a second member, wherein a pairof conductors of the plurality of pairs of conductors is disposedbetween the first member and the second member.
 18. The electricalconnector of claim 17, wherein: the first member comprises a firstpedestal portion and a second pedestal portion, the second membercomprises a third pedestal portion and a fourth pedestal portion, thepair of conductors comprises a first conductor and a second conductor,the first pedestal portion contacts the first side of the firstconductor, the second pedestal portion contacts the first side of thesecond conductor, the third pedestal portion contacts the second side ofthe first conductor, and the fourth pedestal portion contacts the secondside of the second conductor, and the second edge of the first conductoris held adjacent the first edge of the second conductor.
 19. Theelectrical connector of claim 17, wherein the central insulative portionfurther comprises a third member, the third member disposed betweenconductors of the pair of conductors.
 20. The electrical connector ofclaim 17, wherein wafers of the plurality of wafers further comprisereference conductors, the reference conductors disposed at leastpartially around the central insulative portions and configured to pressthe first member towards the second member such that conductors of thepair of conductors are pinched between the first member and the secondmember.